clean up scripts of power library
moved consumer and producer library into power library folder
improved prioritizing of power consumers
Loading skeletons separately (#1180)

Animations are now part of the skeleton, and skeletons are loaded before meshes. They are stored in a map in StdMeshSkeletonLoader. This is only the first part of changes for #1180.
Merge branch 'master' into learning_branch

Conflicts:
	src/lib/StdMeshLoader.h
	src/lib/StdMeshLoaderBinary.cpp
	src/lib/StdMeshLoaderXml.cpp