Break stochastic file into single pseudosources, run them one by one through lisasim and accumulate sum
lisasim now modified to begin at t0 != 0 (but t0 should lie on timestep), with different 2^N durations: verify that cosmic string barycentric have 2^N + padding points
will have to cut out extra data on the edges of datasets within mergeXML.py (synthlisa does not need this)