Using APPRIS tags during transcript selection
See issue #231 for more info
Misc:
adding gencode19 datasources to testdata
adding a checking that ref AND alt don't both == "-" in infer_variant
wiring tx_mode option for gencode in TestUtils which currently didn't do anything
Merge pull request #255 from broadinstitute/lb_231_appris_transcript_selection

Using APPRIS tags during transcript selection