add Genome::File::Vep::Command::ListGenes

this is something that phenotype correlation uses for parallel-by
burden tests.
add subject_column_header field to phenocorr ClinicalData

some things need to know the first column name (it was previously being
shifted off the list of headers)
command to create burden test option file
command to kick off burden test (parallel by mode)
wrapper for burden test
command to collate burden test results
temporarily remove gstat due to complications with git-subtree
Squashed 'lib/perl/Genome/Model/Tools/Germline/gstat/' content from commit 5482dd7

git-subtree-dir: lib/perl/Genome/Model/Tools/Germline/gstat
git-subtree-split: 5482dd79000a25328189dc384f82c1b2adca6f2a
add leading # to the header in vep output of VcfToBurdenMatrix

previously, the output was not a valid vep file so the vep reader would
throw an error.
update phenocorr to use parallel by burden test
move burden test code to the right spot