inspiral_lr.py: Add population model to ranking statistic. Population model information in inspiral_intrinsics.py.

- replace built-in algebraic model with the actual trigger distribution
  from all of O2, marginalized across the entire bank

inspiral_lr.py: added None template_id to random_params because likelihood-ratio code requires it now

dropped in online ranking statistic code

- Param elements now do support None, but not via the .from_pyvalue() method, yet, only via the .build() method.

- not currently used, but this plumbing will be needed to add source population models to the ranking statistic

- combine adjacent segments up to +/- 1 h from the trigger to estimate the trigger rate.
- this is a work-around for the situation in which vetoes slice up the SNR stream so badly that no triggers can be collected, even though very loud injections can still be recovered (which creates apparently impossible candidates)

- V1 must be removed from the coinc rates model in the denominator because
  all coincs will be made to be V1-less in the .__call__() method

- This reverts commit 8d438d4a.
- and fixes the feature
- the problem was start-up transients in the whitener leading to bad PSDs
  at the start of analysis jobs.  this was never a problem before because
  we were averaging over the entire experiment, but now the ranking
  statistic believes there is a brief period of insanely high sensitivity
  at the start of segments, and anything found during that time was given
  far too high a significance.  the fix is to have lloidparts check the
  n-samples property of the whitener that provides the PSD, and disregard
  PSDs until it gets close to the configured average-samples value.

- by finishing the construction of the dataless ranking statistic
- this makes gstlal_inspiral_fake_diststats obsolete, so it is deleted

- mucks things up somehow, don't understand it

- switch numerator and denominator PDFs to a rate.BinnedLnPDF + snglcoinc.LnLRDensity() -based implementation
- add trigger rate tracking feature to denominator, taking advantage of new high-speed coincidence rate machinery in snglcoinc
- add signal rate tracking feature to numerator, taking advantage of pre-computed P(instruments) factors in SNR PDF look-up table
- switch ranking statistic distribution to a rate.BinnedLnPDF -based implementation
- remove search_summary tables, attach all livetime tracking to the trigger rate data in the denominator object

this is a work in progress.  some notable features that are still missing:

- --min-log-L cut based candidate rate reduction feature in gstlal_inspiral is disabled
- online mode for gstlal_inspiral is non-functional