Update directory structure to work with rustpkg
Make Window::create_inner constructor private
Remove stale comment
Simplify extern callbacks
Add note to compilation instructions
Add missing semicolon in README code example
Wrap key modifier bitfield

The key and mouse button callbacks now take a KeyMods struct for the mods parameter. This struct wraps the bitfield, allowing for a nicer way to query what modifiers are currently present.
Add example to KeyMods::contains doc comment
This change removes the need for poll_events on a Window, per issue #31.

It removes the stream-based event handling in favor of a Window-local
map of pointers to registered callback closures. These closures are
owned by the raw C window and are released when the window is destroyed.
Remove extra whitespace.
Merge pull request #32 from larsbergstrom/remove-poll-events

This change removes the need for poll_events on a Window, per issue #31.
Clean up user data accessing by making get_fns a method on Window
Add note about where to find OpenGL bindings
Put notes under an FAQ heading
Update char conversion
Cast from c_int to bool is forbidden. Replace `as bool` by `!= 0`
Merge pull request #34 from sebcrozet/bool_cast

Cast from c_int to bool is forbidden. Replace `as bool` by `!= 0`
Remove stale comment
Merge remote-tracking branch 'bjz/master' into HEAD