Removed unnecessary edit mode switch as per comment by Ghost
Fix for bone weight grouping export. Checks if grouping maps to a bone
correctly now and also finds unweighted vertices correctly
Allow users to have vertex groups which are not named as bones.
Merge remote-tracking branch 'neomonkeus/feature/export_armature' into
feature/export_armature

Conflicts:
	io_scene_nif/nif_export.py
Multiple changes to import/export functions, decompose_srt is more
precise and scale_correction now functions the same as blender scale
function.