Merge pull request #99 from cmr/master

Update submodules + stuff
Update to latest cargo
Merge pull request #100 from Tomaka17/master

Update to latest cargo
Update for language changes
Merge pull request #102 from bjz/update

Update for language changes
Update to Rust nightly
Merge pull request #103 from Tomaka17/master

Update to Rust nightly
Upgraded to latest Rust-Empty
Merge pull request #105 from bvssvni/master

Upgraded to latest Rust-Empty
gl_generator: support passing in extensions