Current Player shape good for Sensor Boundary bad for Collision

[jbtule]

• [x] Make the current shape on Player a sensor shape (sensor = true)
• [x] suggest renaming collision_type to :player_sensor
• [x] fix the reference of symbol :player to player_sensor in create_universe_boundary
• [x] add additional smaller shape to player (and thus space) that will be for collisions of type :player