Bring code up to date with Eq changes in Rust

This contains two kinds of changes:
- TotalEq was renamed to Eq, so where TotalEq was derived before, Eq is
  now derived. This required also deriving PartialEq, since it is
  required by Eq and not derived automatically.
- Where Eq was derived before, derived PartialEq in addition to make it
  compile. This is not equivalent to before (since the old Eq is now
  called PartialEq), but I saw no reason to only make the weaker
  equivalence guarantees provided by PartialEq in those cases.
Fix snake case compiler warning

Since the function in question directly mimics an OpenGL function, I
believe disabling the warning is better than renaming the function.
Merge pull request #166 from bjz/hannobraun-cherry-pick

Rust updates
Fixed deprecation warnings.
Merge pull request #167 from leonkunert/master

Fixed deprecation warnings.
Make building work with Mingw

Applied changes by @imbaczek
Improve documentation for `Window` dropping and silence warning
Merge pull request #171 from bjz/docs

Improve documentation for `Window` dropping and silence warning
Use raw-pointer for returning GL proc address
Fix formatting
Update to latest rustc
Merge pull request #172 from bjz/glproc

Use raw-pointer for returning GL proc address
Merge pull request #170 from bvssvni/master

Make building work with Mingw
Added rust-empty.mk

To build with rust-empty, type

`make link && make -f rust-empty.mk`
Added docs about rust-empty to README
Moved rust-empty specific gitignores
Merge pull request #173 from bvssvni/master

Added rust-empty.mk
Upgraded to latest Rust
Merge pull request #177 from bvssvni/master

Upgraded to latest Rust
Merge remote-tracking branch 'bjz/master' into HEAD