added --disable-massmodel option to turn off installation of lnP_template_signal_BBH_logm_reweighted_mchirp.hdf5. Made madification to .gitlab-ci.yml

- switch ranking statistic to this unconditionally for the October 2018
  open public alert test run.  after the test run and before O3 we will
  introduce more user-friendly plumbing allowing this to work with other
  template banks.
- NOTE:  git-lfs is used for any file ending in .hdf5 in the
  population_models/ tree

add optimized Makefile for gstreamer v1.14 + corresponding patch to remove libgstpythonplugin from gstlal repo

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

- these are being used temporarily for debugging the online pipeline;  this patch is my current state so Chad can pick it up and see if he can make progress