Fix warnings for win32 (#283)

Cargo.toml

@@ -29,7 +29,6 @@ core-graphics = "0.8"
 [target.'cfg(target_os = "windows")'.dependencies]
 winapi = "0.2"
 shell32-sys = "0.1"
-gdi32-sys = "0.1"
 user32-sys = "~0.1.2"
 kernel32-sys = "0.2"
 dwmapi-sys = "0.1"

src/lib.rs

@@ -92,8 +92,6 @@ extern crate kernel32;
 #[cfg(target_os = "windows")]
 extern crate shell32;
 #[cfg(target_os = "windows")]
-extern crate gdi32;
-#[cfg(target_os = "windows")]
 extern crate user32;
 #[cfg(target_os = "windows")]
 extern crate dwmapi;

src/platform/windows/events_loop.rs

@@ -44,7 +44,6 @@ use KeyboardInput;
 use WindowAttributes;
 use WindowEvent;
 use WindowId as SuperWindowId;
-use AxisId;
 
 /// Contains information about states and the window that the callback is going to use.
 #[derive(Clone)]