keep the hand above the terrain #77
add height offset between Hand and Terrain #77

- let the hand fetch the height information from the terrain directly
- make transform/height calculations lazy
include <string> in hand.h. #77
Merge pull request #81 from lanice/Fix_HandPosition_77

Fix hand position 77
Merge remote-tracking branch 'origin/master' into rendering_performance_82

Conflicts:
	src/hand.cpp