MHX importer: Tested with Blender 2.68a. Better FK/IK snapping, which however only works with mhx rig in MH svn.

git-svn-id: https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons@4692 96b784f8-4ae3-dd11-aff7-0030488c597c
undo the workaround of my previous commit for "[#36443] Vertex to UV index doesn't match with 2.68a", because that issue is fixed in blender 2.68a r59343 now.

- deleted not needed workaround for issue [#36443], because it is fixed in blender 2.68a r59343,
- added BMEdge generation to the importer (only for nice doing),
- added undo to operators,
- deleted some unused strings,


git-svn-id: https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons@4694 96b784f8-4ae3-dd11-aff7-0030488c597c