Several fixes for SceneNodeAnimatorCollisionResponse, based on http://irrlicht.sourceforge.net/forum/viewtopic.php?f=7&t=33098&p=290746
Thanks to all people who reported and to JLouisB and kinkreet for the patches:
- Gravity is now fps independent
- Values of gravity now like documented (wasn't 1 unit = 1m before, had been 1m = current frames per second, so maybe 100 units = 1m). 
  Note that jump-values for fps-camera must also change when adapting gravity!
  Several examples got adapted for new ranges
- Pausing timer now pauses animator. Also doesn't reset values anymore with pauses.
- Clones no longer have 1000 times the gravity of original animator.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@5305 dfc29bdd-3216-0410-991c-e03cc46cb475