Added map rotation to libscope
Added map rotation to libscope

A feature to preserve old gid_map and name_map files was added.
Now, old maps are rotated out of the way before new ones are written
from a call into ls_define_scope.

cmusatyalab/opendiamond,cmusatyalab/opendiamond,cmusatyalab/opendiamond,cmusatyalab/opendiamond,cmusatyalab/opendiamond