disable view3d dolly, move, pan -- when the view offset is locked, also corrected fly modes offset lock check
and added ED_view3d_offset_lock_check() to reuse between functions.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56487 954f8c5b-7b00-dc11-b283-0030488c597c