Fix an out of bounds crash in paint example.

The out of bounds error can occur when the window is resized and the
user tries to paint outside of the image.
Merge pull request #61 from bvssvni/master

Upgraded to latest Piston
Merge pull request #62 from bvssvni/master

Handle resize event
Merge pull request #63 from bvssvni/master

Handle focus event
Merge branch 'master' into out-of-bounds
Merge pull request #64 from TyOverby/out-of-bounds

Fix out of bounds error
Add IRC Notifications
Merge pull request #65 from Indiv0/add-irc-notifications

Add IRC Notifications
Merge pull request #66 from bvssvni/master

Upgraded to latest Rust
Added an example about sprite
Merge pull request #67 from Coeuvre/master

Added an example about sprite
Fix the aspect ratio in the gfx cube example

An aspect ratio of 1.0 does not fit the screen resolution, so the rendered cube
looks a bit odd. While fixing this the relation has also been refactored.
Merge pull request #68 from aepsil0n/fix/aspect_ratio

Fix the aspect ratio in the gfx cube example
Upgraded to lastest sprite
Merge pull request #69 from Coeuvre/master

Upgraded to lastest sprite
Upgraded to latest sprite
Merge pull request #70 from Coeuvre/master

Upgraded to latest sprite
Update now that sdl2_game_window doesn't depend on gfx
Remove commented out line
Merge pull request #73 from PistonDevelopers/gfx_update

Update now that sdl2_game_window doesn't depend on gfx