gomu::Application: Add onKeyPress(SDLKey)
Add fullscreen setting capabilities
Add gomu::Font
gomu/State.hpp: Remove extra ;
Add gomu::Texture
gomu::State: Ignore parameters in placeholder methods

The compiler emits warnings for unused parameters.
We can avoid those warnings if we cast the parameters to void.
Merge pull request #12 from crumblingstatue/master

Another pack of improvements