Add MWA telescope and backend codes for SIGPROC-style filterbanks

[bwmeyers]

Previously, MWA pulsar data was exclusively PSRFITS, but we are now producing SIGPROC-style filterbank data occasionally as well, so we need to have some respective telescope and backend machine IDs. Specifically, I added the case for telescope_id = 30 to correspond to MWA and then three related machine_id cases that correspond to the different generations of voltage capture/beamforming capabilities of the telescope:

• 30 = Legacy MWA VCS (MWA-VCS)
• 31 = current MWAX VCS (MWAX-VCS)
• 32 = future real-time beamforming with MWAX (MWAX-RTB)

Also, since the MWA is now expanding (currently at 144T, eventually 256T) I re-labelled the telescope as just "MWA" rather than "MWA128T".

P.S. Happy to remove the comments if you'd prefer.

[scottransom]

Thanks for the PT @bwmeyers! Do you want to add the MWA to python/presto/sigproc.py, src/polycos.c, and bin/get_TOAs.py, as well? The latter two are useful if you are ever doing timing stuff with the PRESTO tools.

[bwmeyers]

Oh yes, that's a good idea! I'll do that in the next few days and update this branch.

[bwmeyers]

Okay that was easier and quicker than I thought... updated both of the python files.

I didn't see anything in src/polycos.c to change - the MWA is already listed there on Line 140 with tempo code u (which is correct).