Add additional options helpful for LBA calibration
Created by: darafferty
I added a few things to DDECal to address some issues @revoltek found with calibration of LBA data (issues #81 (closed) and #99 (closed)):
- add option to restrict propagation to converged solutions only ("propagateconvergedonly")
- add option to flag unconverged solutions ("flagunconverged")
- add an amplitude-divergence check to the rotation+diagonal constraint, as station amplitudes occasionally diverge (some with very high values, some with very low ones) in this mode. The check ensures amplitudes drift by no more than a factor of 5 from the mean over all stations
- add option to flag solutions if this amplitude divergence happens and the solver does not converge ("flagunconverged" + "flagdivergedonly"). All stations will be flagged if any one station is detected to diverge