Trying to get them Shields Regenerating!

v0.1.3-Alpha build.6;
- Fixed static pointers to things that should be static, like Screen
Height/Width.
- Added several checks to remove late game lagg, like bullets/enemies
off the screen, etc.
- Marginally increased the size of the Powerup, Little easier to get
now.
- Elongated the Blue enemies, make them stand out now.
- Added a new Powerup! Regenerate dem Shields! - very rare to come
accross, to rare even.