Confirm fluxcal.py is accurate

[NickSwainston]

Need to confirm/improve:

• Elliptic coordinates are correctly used
• The flux values are correctly decimated
• It works for all bands including the new one
• Clean up the script so it imports get_rcvr() and other functions from common locations
• Some of the grep subprocess calls can probably be done better

[NickSwainston]

I'm going to put the CHIPASS_Equ.fits into the repo but it is 36 MB so we should see if we can trim it of anything unnessisary