MwGui windowManager calls fixed to use MWBase::Environment::get().getWindowManager, filenames in MwGui now comply with naming conventions
Deleted *_* files in MwGui, builds.
Finally eliminated calls to MWBase::WindowManager in constructors
Move NIFSkeletonLoader to a separate file
Use actual classes for properties
Move NIFMaterialLoader to a separate file
Removed non-essential includes from all MWGui header files.
Move the mesh loader to its own source file
Move a method to the Node class
Merge remote-tracking branch 'zini/master' into nifogre
Merge remote-tracking branch 'galdor557/master'

Conflicts:
	apps/openmw/mwgui/travelwindow.cpp
Merge remote-tracking branch 'kcat/nifogre'