Types of calibration tables: 
 * Gain
 * Bandpass
 * Leakage

Current miriad formats:

{{{
#!rst
gains
=============
The gains table contains nants complex antenna gains for nfeeds feeds and nsols solution intervals. 



======  ==============  =========
offset  value           length
======  ==============  =========
0       0               4
4       undef           4 
8       julian date     8
16      gains(2,nants)  8*2*nants
(last 2 lines repeat nsols times)
=================================


bandpass
========
The bandpass table contains nchan * npol * nants complex channel gains.
The value nchan is the sum of all channels in all frequency bands, npol=1 or 2.

======  =================== ==================
offset  value               length
======  =================== ==================
0       0                   4
4       undef               4 
8       g(nchan,npol,nants) 8*nchan*npol*nants
======  =================== ==================



freqs
=====
A separate table "freqs" is maintained with the frequencies for each of nspec bands (or spectra).
The item freq is the frequency for the first channel, df gives the channel spacing

======  =================== ==================
offset  value               length
======  =================== ==================
0       0                   4
4       undef               4 
8       nschan              4
16      freq                8
24      df                  8
(last 3 lines repeated nspec times)
==============================================


leakage
=======
todo..

}}}