Add visibility-related functions to window
Merge pull request #93 from tomaka/visibility

Add visibility-related functions to window
Retrieve the monitors and their info for osx
Switched to own repos for osx bindings
Merge pull request #97 from DavidPartouche/cocoa_monitors

Retrieve the monitors and their info for osx
Merge branch 'master' of http://github.com/tomaka/gl-init-rs
Update for changes in gl-rs