PolyConnectivity: Added range based circulators courtesy of Kenshi Takayama. (Thanks!)
Also rearranged the code a bit in order to have all range based stuff
in one place and limited line width to 80 chars.

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1035 fdac6126-5c0c-442c-9429-916003d36597