- add knife project to toolbar.
- when running knife project, disable vertex selection since it may select areas between the newly cut regions.
  add EDBM_selectmode_disable() function since loopcut does this too.
- (optimization) avoid looping over all geometry when flushing and no selection exists.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55445 954f8c5b-7b00-dc11-b283-0030488c597c