Added collision detection for main object.
Updated collision. Fixes #20
Added ProximityManager utility. Not really tested in this context but
worked in platformer1.Closes maximx1/PyPlatformerEngine#17
Added controlling entity marker. Fixes #15
Added basic image loading via spritesheet without animations. Closes #10
Added left and right velocity. Closes #23
Added reset of deltaX to the default action component.
Merge pull request #27 from maximx1/develop

Ready for v1.1.0.0