Auto merge of #141 - nox:core-graphics, r=Ms2ger

Update core-graphics to 0.4

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Cargo.toml

@@ -3,7 +3,7 @@ name = "cocoa"
 description = "Bindings to Cocoa for OS X"
 homepage = "https://github.com/servo/cocoa-rs"
 repository = "https://github.com/servo/cocoa-rs"
-version = "0.4.4"
+version = "0.5.0"
 authors = ["The Servo Project Developers"]
 license = "MIT / Apache-2.0"
 
@@ -15,5 +15,5 @@ crate-type = ["rlib"]
 block = "0.1"
 bitflags = "0.7"
 libc = "0.2"
-core-graphics = ">=0.2, <0.4"
+core-graphics = "0.4"
 objc = "0.2"