The MARK element will now provide optimizable parameters from coupled-beam
eigen-analysis[1] if COUPLED_FITPOINT=1.
The CBSCAT element was added, providing simulation of Compton backscattering using a
method based on [2], as well as less approximate methods.
The CHANGE_T feature of RFCA has been enhanced so that subtracted time values are
accumulated in extended-precision registers, the values from which are used to provide
long-scale time offsets (e.g., for slowly-varying, non-harmonic elements) and phase offsets
modulo 2π to rf elements. For the latter, this is important if the rf frequency is not a
subharmonic of the frequency for which the time value changes are done.