Fixes, optimizations

Reviewing a big portion of the code to clean up old bugs hanging around. Small but important fixes and optimizations were done since the release came out. I've added multilevel placing of units in the encounter phase so that you always meet'em even standing on a mountain. Also I've detected a serious node culling issue I was not aware of yet that disabled the whole culling - now it's working again resulting in big boost of performance that we've lost on the way maybe months ago. In the end the working culling caused me to do some tricky zero quad placement to the UI base node (which is in jme's ortho queue, only 2D things for UI) to make sure it is not culled. A bit confusion maybe in jME or even a bug or two? Now tonight I've hunted down another old issue - the jumpy foliage and vegetation bug. Making the time counter field static in the TrimeshGeometryBatch solved the problem.