testLicense, printStackTrace to log, verifiesOrAssertions, strings.xml

- 'WaitActionTest' - 'ActionFactory.createDelayAction(...)' returns a WaitAction to provide 'getTime()'
- add 'PhysicsTestUtils.java' to IGNORED_FILES in 'CheckForVerifiesOrAssertionsTest.java'
- add temp test to 'PhysicsBrickPreparatorTest' to pass the 'CheckForVerifiesOrAssertionsTest'
- add rough draft of german version of physics-strings
- remove redundant strings in string.xml
    rm 'brick_turn_left_speed' (identically string - 'brick_turn_left')
    rm 'brick_turn_right_speed' (identically string - 'brick_turn_right')
Merge pull request #1013 from Catrobat/physicsCatroidSourceTestFix

testLicense, printStackTrace to log, verifiesOrAssertions, strings.xml