XLALGenerateSimBurst():  move peak time initialization here

- the logic is that XLALGenerateSimBurst() constructs the h+ and hx
  corresponding to a row in a sim_burst table, and the peak time is part of
  the information carried by the row, so the h+ and hx that get returned
  can reflect that.  note that the time slide offset is *not* applied, as
  that required information spanning multiple tables.
lalapps_run_sqlite: allow XML files to be processed