fix some kind of weird bug with the last commit

gimbal.io.Keyboard didn't get deleted for whatever reason.
Added Vector2D class

Vector2D is a representation of a vector. It uses the cartesian
horizontal and vertical length to store its data because that is easier
to use for movement and seems a better way of storing the data. It can
be accessed using both concepts of a vector however, potentially
allowing for polar coordinate systems on higher level ingame objects in
the future. I'm not sure if the setMagnitude method is the fastest way
of doing what it does, but at this point I don't even care. The other
methods should all be somewhat fast, I think. If I was thorough I would
do tests, but I'm lazy.
Added rendering hints, secured Game dimensions

Currently implemented rendering hints tell Graphics objects to favor
quality over speed. Somehow this has lead to an increase in fps on my
system, but perhaps not on all systems. I will add options in the future
to customize these settings.

Game.width and Game.height have been made private so not everyone can
use them all the time. That's a little too important of a resource to
make public, and the static thing could even become a problem when it
comes time to make the Artillery Toolkit.