IDR4 update
IDR4 update

Changes were made to accommodate IDR4 catalogue. Although changes were minor to the catalogue, the following was altered in the code:
 - get_frequency( ) now  returns 'wide' (instead of 'deep') if the user gives --central_frequency=< | white | deep | wide | w | >.
 - to_Aegean_table( ):
    - now takes peak_flux directly from table instead of calculating
    - all white image dependent parameters look for 'wide', no longer 'deep'
    - flags have all been set to 0 (flags do not exist in IDR4)
    - calc_peak_flux( ) is now redundant.
- default input catalogue is now ".../Data/IDR4/GLEAMIDR4.fits"
AstroRobin/GLEAM-RESID