tree.py: put prefactor to 1 and pad the equal mass line as well as remove mass scaling of deltas and increase metric tolerance

gstlal_idq_trigger_gen: added option to turn on hdf file writing with dataframes, changed string concatenation scheme for writing trigger ascii files to disk when using dataframes

idq_aggregator.py: fixed get_dataset_by_range function for level 1 aggregation, fixed buf in gps_to_index

gstlal_idq_trigger_gen: removed empty file creation if hdf5 files not generated, idq_multirate: cleaned up unnecessary arg, fixed typo in max_rate

- add --full feature to enable population of all possible PDFs
- add --full-fragment feature to enable parallelization
- add --seed / --seed-cache feature to enable merging of PDFs generated in parallel
- add process metadata to the output file to record how it was constructed
- remove make_snr_pdf_cache.py from share/ as it is now redundant

- and change message from "... SNR PDF" to "... candidates"

- instead of a default keyword argument of .quantize_horizon_distances(), store it as an instance attribute
- store the value in the XML PDF cache, and retrieve on load
- update pre-computed cache in share/ to new format (= manually add min_ratio Param to XML tree)

- don't gzip files that are already gzip'ed

- remove superfluous array slice operations
- future-proof integer divisions
- "inline" some algebra to reduce swig interaction overhead