Backup.
Backup.
Backup.
Backup.
Reimplemented the operator=() in all the id space iterators so that if the right hand side of the operator is unattached then the left hand side is detached.

On Linux:
SST make check runs successfully, SCT make check runs successfully, SCT test_all.csh runs successfully.

Still need to test on Windows.
Addded cells_cells_constant sec_rep_descriptor.