Changed a few lines in character blocking code.

I attempted several if-else-if conditions to make enemies who are pushed
back collide with impassable tiles or fall through passable ones. None
of the logic really worked, so I settled with original code with a
couple changes.
Merge pull request #7 from MikePaNtZ/development

Development
Added background music and laser sounds. Jump animation restored.

Tom and I worked on these fixes.
Merge pull request #28 from Daikatana/master

Added background sounds and laser sound. Jump animation restored