Actor Bugfix (0.13.0 Alpha)

This update adds a new BlockRenderer for rendering hexagons or other things that should be rendered in a staggered fashion.  With the introduction of some art and adjustments to remove physics-related tasks, this game engine could now easily be used as a hexagonal mapping program.

This also includes fixes for a number of issues with Actors.  Their bouncing should now be stable and correct.  They shouldn't tunnel through and stick in the edges of the world anymore, either.

Additionally, there are settings in the config file to determine if concave corners between blocks should be treated as slopes.  This is independently  adjustable for top and bottom slopes.

My plan is to next add support for blocks to have varying physical properties, such as coefficient of restitution and friction.  Then I'll tackle giving actors the ability to detect collisions and/or have their own, unique behaviors.