Building on windows: Glutin: not all trait items are implemented

[TyOverby]

$ cargo build
   Compiling glutin v0.6.1 (https://github.com/jwilm/glutin?rev=cc64178d39a1fa06b2c5403117e5e0ef24deeac4#cc64178d)
error[E0046]: not all trait items implemented, missing: `clear_current`
   --> C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\api\wgl/mod.rs:156:1
    |
156 | impl GlContext for Context {
    | ^ missing `clear_current` in implementation
    |
   ::: C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\lib.rs
    |
136 |     fn clear_current(&self) -> Result<(), ContextError>;
    |     ---------------------------------------------------- `clear_current` from trait

error[E0046]: not all trait items implemented, missing: `clear_current`
   --> C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\api\win32/mod.rs:372:1
    |
372 | impl GlContext for Window {
    | ^ missing `clear_current` in implementation
    |
   ::: C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\lib.rs
    |
136 |     fn clear_current(&self) -> Result<(), ContextError>;
    |     ---------------------------------------------------- `clear_current` from trait

error[E0046]: not all trait items implemented, missing: `clear_current`
   --> C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\platform\windows/mod.rs:124:1
    |
124 | impl GlContext for HeadlessContext {
    | ^ missing `clear_current` in implementation
    |
   ::: C:\Users\tyoverby\.cargo\git\checkouts\glutin-2b5ecc80feb2e4c5\cc64178\src\lib.rs
    |
136 |     fn clear_current(&self) -> Result<(), ContextError>;
    |     ---------------------------------------------------- `clear_current` from trait

error: aborting due to 3 previous errors

error: build failed

[jwilm]

Thanks for filing these!

Going to continue tracking them as part of #28.