First version of enemy shooting.

Lots more to do with enemy shooting and AI, but this is a working first
version.
Merge branch 'development' of https://github.com/Lakon/PiN into development
Merged character swapping with enemy shooting
Merge pull request #5 from Lakon/development

Development
Merge pull request #20 from Lakon/development

Added Health Bars
Merge pull request #6 from MikePaNtZ/development

Development
Added bullet deflection by shield

The bullets from enemies are too fast and too powerful. We need a
defense against them. Enter the shield!
Merge pull request #15 from Daikatana/master

Added shield deflection