Updating mac `msprior` and `msbayes.pl`.

Updating both old and new `msprior` and `msbayes.pl` binaries in
the mac bin.
Updating linux `msprior` and `msbayes.pl`.

Updating `msprior` and `msbayes.pl` executables in linux bin.
Adding fasta and config files to test data.
Adding tests to `test_msbayes_priors.py`.

Adding tests to verify taxon sorting and tau draws.