auto merge of #4575 : mttr/servo/warnings, r=jdm

Notes:

* This adds `#![allow(missing_copy_implementations)]` to components/*/lib.rs. I'm not sure how to approach the missing Copy warnings (are there things for which Copy should NOT be implemented, and how can I tell?) so I stuck this in to make life easier when looking through the warnings. I can easily remove this if necessary. 
* This leaves the following type of warnings, which I couldn't figure out how to approach (I'll investigate it later if no one else wants to).
```
css/matching.rs:72:23: 72:35 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:72         this_as_query.equiv(other)
                                         ^~~~~~~~~~~~
css/matching.rs:95:10: 95:49 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:95 impl<'a> Equiv<ApplicableDeclarationsCacheEntry> for ApplicableDeclarationsCacheQuery<'a> {
```

components/gfx/lib.rs

@@ -6,6 +6,7 @@
 
 #![deny(unused_imports)]
 #![deny(unused_variables)]
+#![allow(missing_copy_implementations)]
 
 #![feature(phase)]
 #[phase(plugin, link)]

components/gfx/paint_context.rs

@@ -29,6 +29,7 @@ use servo_util::geometry::{Au, MAX_RECT};
 use servo_util::opts;
 use servo_util::range::Range;
 use std::default::Default;
+use std::f32;
 use std::mem;
 use std::num::{Float, FloatMath};
 use std::ptr;
@@ -383,13 +384,13 @@ impl<'a> PaintContext<'a> {
         let box_BR = box_TL + Point2D(bounds.size.width, bounds.size.height);
 
         let rad_R: AzFloat = 0.;
-        let rad_BR = rad_R  + Float::frac_pi_4();
-        let rad_B  = rad_BR + Float::frac_pi_4();
-        let rad_BL = rad_B  + Float::frac_pi_4();
-        let rad_L  = rad_BL + Float::frac_pi_4();
-        let rad_TL = rad_L  + Float::frac_pi_4();
-        let rad_T  = rad_TL + Float::frac_pi_4();
-        let rad_TR = rad_T  + Float::frac_pi_4();
+        let rad_BR = rad_R  + f32::consts::FRAC_PI_4;
+        let rad_B  = rad_BR + f32::consts::FRAC_PI_4;
+        let rad_BL = rad_B  + f32::consts::FRAC_PI_4;
+        let rad_L  = rad_BL + f32::consts::FRAC_PI_4;
+        let rad_TL = rad_L  + f32::consts::FRAC_PI_4;
+        let rad_T  = rad_TL + f32::consts::FRAC_PI_4;
+        let rad_TR = rad_T  + f32::consts::FRAC_PI_4;
 
         fn dx(x: AzFloat) -> Point2D<AzFloat> {
             Point2D(x, 0.)
@@ -572,29 +573,29 @@ impl<'a> PaintContext<'a> {
         path_builder.arc(Point2D(bounds.max_x() - radii.top_right,
                                  bounds.origin.y + radii.top_right),
                          radii.top_right,
-                         1.5f32 * Float::frac_pi_2(),
-                         Float::two_pi(),
+                         1.5f32 * f32::consts::FRAC_PI_2,
+                         f32::consts::PI_2,
                          false);                                                            // 3
         path_builder.line_to(Point2D(bounds.max_x(), bounds.max_y() - radii.bottom_right)); // 4
         path_builder.arc(Point2D(bounds.max_x() - radii.bottom_right,
                                  bounds.max_y() - radii.bottom_right),
                          radii.bottom_right,
                          0.0,
-                         Float::frac_pi_2(),
+                         f32::consts::FRAC_PI_2,
                          false);                                                            // 5
         path_builder.line_to(Point2D(bounds.origin.x + radii.bottom_left, bounds.max_y())); // 6
         path_builder.arc(Point2D(bounds.origin.x + radii.bottom_left,
                                  bounds.max_y() - radii.bottom_left),
                          radii.bottom_left,
-                         Float::frac_pi_2(),
-                         Float::pi(),
+                         f32::consts::FRAC_PI_2,
+                         f32::consts::PI,
                          false);                                                            // 7
         path_builder.line_to(Point2D(bounds.origin.x, bounds.origin.y + radii.top_left));   // 8
         path_builder.arc(Point2D(bounds.origin.x + radii.top_left,
                                  bounds.origin.y + radii.top_left),
                          radii.top_left,
-                         Float::pi(),
-                         1.5f32 * Float::frac_pi_2(),
+                         f32::consts::PI,
+                         1.5f32 * f32::consts::FRAC_PI_2,
                          false);                                                            // 1
     }
 

components/gfx/platform/freetype/font.rs

@@ -28,7 +28,7 @@ use freetype::tt_os2::TT_OS2;
 use std::mem;
 use std::num::Float;
 use std::ptr;
-use std::string;
+use std::string::String;
 
 use std::sync::Arc;
 
@@ -121,10 +121,10 @@ impl FontHandleMethods for FontHandle {
         self.font_data.clone()
     }
     fn family_name(&self) -> String {
-        unsafe { string::raw::from_buf(&*(*self.face).family_name as *const i8 as *const u8) }
+        unsafe { String::from_raw_buf(&*(*self.face).family_name as *const i8 as *const u8) }
     }
     fn face_name(&self) -> String {
-        unsafe { string::raw::from_buf(&*FT_Get_Postscript_Name(self.face) as *const i8 as *const u8) }
+        unsafe { String::from_raw_buf(&*FT_Get_Postscript_Name(self.face) as *const i8 as *const u8) }
     }
     fn is_italic(&self) -> bool {
         unsafe { (*self.face).style_flags & FT_STYLE_FLAG_ITALIC != 0 }

components/gfx/platform/freetype/font_list.rs

@@ -23,7 +23,7 @@ use fontconfig::fontconfig::{
 use libc;
 use libc::c_int;
 use std::ptr;
-use std::string;
+use std::string::String;
 
 static FC_FAMILY: &'static [u8] = b"family\0";
 static FC_FILE: &'static [u8] = b"file\0";
@@ -38,7 +38,7 @@ pub fn get_available_families(callback: |String|) {
             let mut family: *mut FcChar8 = ptr::null_mut();
             let mut v: c_int = 0;
             while FcPatternGetString(*font, FC_FAMILY.as_ptr() as *mut i8, v, &mut family) == FcResultMatch {
-                let family_name = string::raw::from_buf(family as *const i8 as *const u8);
+                let family_name = String::from_raw_buf(family as *const i8 as *const u8);
                 callback(family_name);
                 v += 1;
             }
@@ -73,7 +73,7 @@ pub fn get_variations_for_family(family_name: &str, callback: |String|) {
             let font = (*matches).fonts.offset(i);
             let mut file: *mut FcChar8 = ptr::null_mut();
             let file = if FcPatternGetString(*font, FC_FILE.as_ptr() as *mut i8, 0, &mut file) == FcResultMatch {
-                string::raw::from_buf(file as *const i8 as *const u8)
+                String::from_raw_buf(file as *const i8 as *const u8)
             } else {
                 panic!();
             };
@@ -112,7 +112,7 @@ pub fn get_system_default_family(generic_name: &str) -> Option<String> {
         let family_name = if result == FcResultMatch {
             let mut match_string: *mut FcChar8 = ptr::null_mut();
             FcPatternGetString(family_match, FC_FAMILY.as_ptr() as *mut i8, 0, &mut match_string);
-            let result = string::raw::from_buf(match_string as *const i8 as *const u8);
+            let result = String::from_raw_buf(match_string as *const i8 as *const u8);
             FcPatternDestroy(family_match);
             Some(result)
         } else {