Expand Input System

[AlexvZyl]

We need more functionality such as isKeyDown(), isKeyUp(), isMouseDown(), isMouseUp() etc. The way we currently keep track of certain key states is not ideal since we are limited in the combinations we can make. We do not have to track these states since GLFW does that for us.

Also, we should make using keys easier by adding our own naming convention to Lumen::Key and Lumen::Mouse. This is going to be important for remapping keys.