fix ifOnEdgeBounce logic for CAT-1060

change repositioning logic
adapt tests
differ between horizontal and vertical border
Merge pull request #1038 from Catrobat/physics_CAT-1060_IfOnEdgeBounce

fix ifOnEdgeBounce logic for CAT-1060
CAT-1058 initial commit

Testing collisions between two dynamic and one dynamic and
one static object by comparing velocities before and after collision