Add GLES2 extension API bindings and some fixes.
Add crate lib
Merge pull request #67 from webconvforge/recrack

add EGL stuffs
Build with make instead of rustpkg.
Merge pull request #68 from metajack/unrustpkg

Build with make instead of rustpkg.
Revert rust upgrade.
Merge pull request #69 from metajack/revert-rustup

Revert rust upgrade.
Add RUSTFLAGS for OS X flavors.
Don't use glBufferData on 10.6.
Upgrade to latest Rust.