Move utility functions from mball to mathutils

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@60851 954f8c5b-7b00-dc11-b283-0030488c597c
Remove paranoid check which was marked as unneeded for a while already

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@60852 954f8c5b-7b00-dc11-b283-0030488c597c