Modify PhysicsActionTestCase, HideCollisionTest

Provide two sprites in `PhysicsActionTestCase.class` [ sprite1, sprite2
]
Add `PhysicsActionTestCase.setContactListener()` and hooks to use for
the action-tests
Add `HideActionAndCollisionTest`

Conflicts:
	catroidTest/src/org/catrobat/catroid/test/physics/actions/IfOnEdgeBouncePhysicsActionTest.java