- when plugin cannot be loaded

- move more performance-critical methods into the C layer, this time the
  rich comparison methods

- recognizing that nothing uses the trigger class defined in
  snglinspiraltable except the trigger generator and its coincidence
  machinery, flatten the inheritence tree by one to improve attribute
  look-up performance

- move performance-critical methods to the C layer

- forgot a line from e3b38b0d

- use .template_id to check for template equality

- the coincidence code will now rely on the .template_id attribute to
  determine which template each trigger has come from.  this patch adds an
  assert to confirm that that is safe to do.

- a thinko was causing it to include one too many segments below the bound
  than required to satisfy the criterion.  it wouldn't lead to incorrect
  results, just a small slow-down.  ligo.segments now provides an
  implementation of this function, but that version of ligo.segments is not
  yet in production so we need to retain this implementation here for the
  time being.

gstlal_compute_strain:  Added a trick to make it possible to high-pass filter the inverse sensing path at a lower sample rate without losing information above the Nyquist rate.

gstlal-calibration:  Many small chenges, including conditional reading in of a config file parameter in gstlal_compute_strain and DCS config file updates.

gstlal-calibration/tests/check_calibration/Makefile:  Fixed easy raw frame maker so that it only makes raw frames to fill in any gaps.

- avoid an attribute look-up inside lower_bound_in_seglist()

gstlal_compute_strain:  Better way to to check for config file options that may not be present.  New option to flip sign of the pcal channel.

This reverts commit 62952454.