Removed command pointers from input service, and changed guiElement so click functors are called on clickUp rather than down
Numerous api changes including:

addition of action functors for keyboard input,
moving of key action handling from action down to action up,
replacement of stack "vector" stack with real stack,
implementation of starting states based on new state actions and the removal of state registration.
Merge pull request #110 from n8ebel/dev

Dev