Added Basic Grow Power Up

Needs encapsulation. We should think about how we want to organize this
before we get much farther.
Added Stats, Extra Life Box, Better Documentation
Temp immunity and blinking when big after enemy hit
Added player bouncing when you jump on an enemy.
Merge pull request #3 from mlewisno/pauls_new_branch

Added player bouncing when you jump on an enemy.
Merge pull request #2 from mlewisno/GrowPowerUp

Grow power up