correct exporing of loose edges, obj spec defines faces as needing at least 3 verts (even though 2 vertex faces are in fact quite common).
now export these as lines.


git-svn-id: https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons@4575 96b784f8-4ae3-dd11-aff7-0030488c597c
Fix import image as plane to work in Blender Game engine mode too.

git-svn-id: https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons@4576 96b784f8-4ae3-dd11-aff7-0030488c597c
add support for writing smooth groups for OBJ


git-svn-id: https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons@4577 96b784f8-4ae3-dd11-aff7-0030488c597c