Generate docs for headless functionnalities too
Merge pull request #174 from tomaka/travis-docs-headless

Generate docs for headless functionnalities too
Update for changes in Send/Sync traits
Merge pull request #178 from tomaka/update-rustc

Update for changes in Send/Sync traits
Use gl_common and gl_generator from crates.io
Merge pull request #179 from tomaka/use-cratesio

Use gl_common and gl_generator from crates.io
Bump version number
Unify WindowBuilder and HeadlessRendererBuilder for easier implementations
Add `build_strict` function on builders
Add missing `with_*` functions