Fix class name for testing Ai
Normalize angles in Tank

Angle value can be between 0..360
Reset actions hash after each update
Remove unnecessary puts
Remove test robots from git
Fix .gitignore
Add possibility to decelerate for Ai
Render radar and rotate tank body
Fix typos in specs
Allow speed to be set during initialization
Extract Movable module
Refactor movable
Add Bullet class
Remove gosu from Tank, it is included in Movable
Add possibility fo Ai to fire a bullet
Fix a typo in the spec
Change way of the arena initialization