Adding IntelliJ files to the .gitignore
Merge pull request #16 from genomebridge/updating-gitignore

Adding IntelliJ files to the .gitignore
Adding two new fields, 'featureType' and 'source', to ADAMRecord.

The existing implementation was parsing these into a single field, the
'trackName'.  That's fine, but we also need (for GTF/GFF files where
we'll be extracting and reconstructing gene models) a version of these
fields separated out in their original form.