Updating `parsing` module.

Updating `get_result_indices` method of `DMCSimulationResults` class.

The method now `glob`s for a less restrictive results file path that
actually matches two types of output files to increase the chance that
the indices can be parsed.

Also, updating `NumberOfDivergencesSummary` class. Adding checks
for zero division problems during bayes factor calculations.
Updating `dmc_plot_results.py` script.

Fixing bug in finding posterior summary files. Also, adding flexibility
in plot dimensions depending on the number of taxon pairs.