Merge pull request #5 from SanishThomas/master

Map texture url change
added map configuration, pre-render map, preload images
consolidated debug/drawing entity collision areas
added dirt and grey block graphics
added configurable images to Blocks
added map patterns
added Dirt1 map
updated tank movement sprite animation
prerender blocks
simplified map configurations, removed Patterns
added map config documentation
added BigN map
always target away from the tank when shooting
fixed removing undefined tank
added polygons to map configuration
added Tank/Poly collisions
began adding Bullet/Poly collisions
Bullet polygon