- XLALReadTimestampsFileConstrained(), and XLALReadMultiTimestampsFilesConstrained(),
  with additional input arguments 'const LIGOTimeGPS *minGPS, const LIGOTimeGPS *maxGPS'
  to constrain returned timestamps to within that [range)
- provides backwards-compatible wrappers XLALReadTimestampsFile()
  and XLALReadMultiTimestampsFiles()