licenses added, 2 extra levels + enemies die now :D

I've added the licenses for the models I've used from Blendswap to the newly uploaded project. Also 2 more levels are added, a swamp level and what will be eventually an ice level. All very basic now and most of the object placement is copy pasted from previous levels.

Also enemies should be killable now, there was a small oversight that caused them to be invincible.