read “OQ” attr from structured SAMRecord field

converting into and out of BAM using ADAM was dropping the “OQ” attr;
HTSJDK puts it in its own field but ADAM was looking for it in the
catch-all attributes field.
Merge pull request #449 from ryan-williams/origqual

read “OQ” attr from structured SAMRecord field
[ADAM-348] Stores original position and original cigar during realignment.
Addresses issue #348 in the adam project.
Merge pull request #417 from niranjan93/NK_schema_tags

Stores original position and original cigar during realignment.
Better null handling for isSameContig utility
Merge pull request #453 from massie/is-same-contig

Better null handling for isSameContig utility
Update the contribution guidelines
Merge pull request #447 from massie/contribution

Update the contribution guidelines
[ADAM-454] Add serializers for Avro objects which don't have serializers.
Merge pull request #455 from fnothaft/add-serializers

[ADAM-454] Add serializers for Avro objects which don't have serializers