Added function to rotate an image (in progress).
Actually be able to set the angle argument.
Make projectiles look better.

Adjusted the projectile images to have their trailing edges at the
center of the hex (makes the initial shot look better).

Arbitrarily shorten the flight distance so projectiles don't overshoot
their targets (because the image is no longer centered).

Allow them to rotate correctly instead of using fixed images.
Removed unused function, updated readme.