Merge pull request #3 from cmr/master

Bunch of fixes
Merge pull request #4 from cmr/master

Extensions revamp
Remove stale todo
Rename generator.rs to main.rs as per rustpkg conventions
Fail on getopts error, use default value when missing --type option
Merge pull request #5 from cmr/master

Fix the generated gl.rs
Default to core profile
Use *mut for non-const function parameters, omit c_void return types
Add LICENSE and AUTHORS, update README
Update examples
Update .gitignore
Implement --full option that generates complete API.
Clarify help text for --full
Special-case gl::TRUE and gl::FALSE to generate as GLbooleans
Remove struct-style generator

This proved to be of little utility or interest, so… zap!
Merge branch 'refs/heads/master' into full-opt
Simplify types relating to registry filtering
Add Arseny Kapoulkine to AUTHORS
Glob imports. Replace loop keyword
s/while true/loop