Fix bug that trackSections did not get removed, because collider was set inactive and did not collide with BorderRegion.
Remove unused entities from COB.
Merge branch 'master' of github.com:V-Play/AGJ13

Conflicts:
	qml/Level.qml
	qml/entities/Obstacle.qml
Merge branch 'master' of github.com:V-Play/AGJ13