Added halo color transition

Halo now slowly transition to the new color for added effect.
Also has the side effect of making the player glow white at the
beginning of the level (which may or may not be a good thing)
Made color wheel selector visually clear

It may look a little crappy but we'll see.
Added a restart level button
Color halo now indicate which color is selected

Color halo changes its transparency depending on if the color it
represents is selected or not. This might even remove the need for the
color wheel.