Collision cleanup

[einarf]

• Split up the spatial hash module
• Moved geometry functions to a separate module
• Cleaned up geometry module and exposed all functions
• Moved some geometry functions into math
• Make SpatialHash a public member
• Clean up SpatiaHash with proper typing
• Use sets in SpatialHash for overall better perfromance and protection against duplicates
• Various optimizations in sprite and spritelist
• Clean up deprecated stuff in SpriteList
• Moved some functions out of the arcade module
• Removed deprecated SpriteList is_static
• added math.round_fast
• Added several missing docstrings
• Added get_sprites_in_rect
• Added SpatialHash.get_sprites_near_rect
• Many small optimizations
• SpriteList.update_x methods are not private
• Added more unit testing