Updated changelog, updated doxyfile to 1.8.6

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1064 fdac6126-5c0c-442c-9429-916003d36597
exposed property handles and mesh property functions (add, remove, get, set)

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1065 fdac6126-5c0c-442c-9429-916003d36597