Merge pull request #1 from AlphaBravo314/master

Create PlayerWeapon.java
Update from original repo
Merge branch 'master' of https://github.com/AlphaBravo314/SpaceInvaders.git
Update from NGSE
Update from NGSE repo
Up to date with NGSE repo
Update from NGSE repo
Bullet will delete after leaving screen
BulletCollisionHandler should be working. empty die() method added to
Alien and Alien Boss and empty loseHealth() method added to player,
which will need to be implemented.