Allow for other calibration methods

[rfshipman]

In the develop branch, there is only one calibration method possible. cal_weightedHOTs

Line 581 fixme: make this conditional --> if calmethod == 'cal_weightedHOTs'
ta[i0,:], cflags_OTF[i0], Tsys_OTF[i0], rms_OTF[i0] = cal_weightedHOTs(spec_OTF[i0,:], band,

The definition for cal_weightedHOTs is present so a condition based on calmethod works.

[rfshipman]

band1_tests branch implements 2 other calibration methods and the conditional statement. using the following:

   if calmethod == 'cal_weightedHOTs':
        for i0 in range(n_OTF):
            # fixme: make this conditional.  if calmethod == 'cal_weightedHOTs'
            ta[i0,:], cflags_OTF[i0], Tsys_OTF[i0], rms_OTF[i0] = cal_weightedHOTs(spec_OTF[i0,:], band, cflags_OTF[i0], hgroup, hgroup[i0], ghots, tsys, yfac, int(polyorder), despurmethod)

    elif calmethod == 'cal_scaleHOTs':
        for i0 in range(n_OTF):
            ta[i0,:], cflags_OTF[i0], Tsys_OTF[i0], rms_OTF[i0] = cal_scaleHOTs(spec_OTF[i0,:], band, cflags_OTF[i0], hgroup, hgroup[i0], ghots, tsys, yfac, int(polyorder), despurmethod)

    elif calmethod == 'cal_combineHOTs':
        for i0 in range(n_OTF):
            ta[i0,:], cflags_OTF[i0], Tsys_OTF[i0], rms_OTF[i0] = cal_combineHOTs(spec_OTF[i0,:], band, cflags_OTF[i0], hgroup, hgroup[i0], ghots, tsys, yfac, int(polyorder), despurmethod)
           

    else:
        print('Choose an implemented calibration method')
        break