relax SVN archive

Implemented the create_mc_data() method.

In the 1.2 line, this was simply aliased to the return_data() method.

Updated the return_error() method to accept the spin_id arg.

This change doesn't actually do anything.

Updated create_mc_data() and sim_pack_data() to accept the spin_id yielded by base_data_loop().

Made the base_data_loop() generator method accessible to the specific analyses.

Created the base_data_loop() generator method for the base class for looping over spins.

Modified the create_data() method to use the unimplemented base_data_loop() generator method.

Removed some more useless functions.

Removed a useless function.

Created the generic_fns.pcs module, although nothing will work yet.

Activated the PCS user functions.