change GodManipulators navigation mechanics

W/S now moves the camera to -z/z (still relative to lookAt-vector) instead forward/backward in lookAt direction.
--> the height is fixed while 'flying' over the world.
add rotation to GodManipulator navigation (key Q/E).

the camera (horizontally) rotates around a center which is in front of the camera.
at the moment that center is hard coded, soon it should be a fix (maybe variable but fix) distance given by the game.
Merge remote-tracking branch 'origin/osgTerrainTest' into navigation_godmanipulator
set configs to generate small terrain at beginning
Merge pull request #1 from lanice/navigation_godmanipulator

Navigation_godmanipulator and osgTerrainTest