Add support for numerical relativity data in SimBurstTables

The existing implementation of the SimBurstTable code does not allow for the injection of numerical relativity waveforms. This is a desirable feature for e.g. supernova and ADI waveforms. This branch implements such support in a way analogous to in a SimInspiralTable, and allows xml files with these columns to be written and read.

I'm very open to suggestions for better ways to handle this; this seemed like a good, quick solution a couple of years ago when I was preparing the O1 MDC for the burst group, but I'm prepared to make changes to minke (the burst MDC package) to allow for an alternative implementation if that seems more sensible.

There is a corresponding merge request to add support for such files to glue as well: glue!37 (closed)