Patch [#37115] Surface split and separate operators

Added surface support to recent curve split operator, completing quick hack todo
Updated nurbs separate operator to make use of new split logic, completing tools todo
Added 'Delete segment' option to surfaces and improved surface duplication, used for split/separate



git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@60834 954f8c5b-7b00-dc11-b283-0030488c597c