proper handling of keyboard repeat events after update to glfw3

Keyboard onKeyReleased events are being repeatedly fired even before the you physically release the keyboard. 
This appears to have happened with the move from glfw2 to glfw3 which now enabled REPEAT by default, see:
http://www.glfw.org/docs/3.0/moving.html#moving_repeat

To preserve the original behaviour where the onKeyReleased event is fired only when the keyboard key is actually physically released, we need to ignore the GLFW_REPEAT action, see:
http://www.glfw.org/docs/3.0/group__input.html#ga592dd1919f8a1dc7576b13cdd8b7b695