Checking for key exists.
Merge pull request #653 from jaredbischof/develop

Checking for key exists.
Reverting last edit.
Merge pull request #654 from jaredbischof/develop

Reverting last edit.
added option to change sequence type
Merge pull request #655 from paczian/develop

added option to change sequence type
only add external metadata ref if IDs exist
Merge pull request #656 from teharrison/develop

only add external metadata ref if IDs exist
Merge pull request #657 from MG-RAST/develop

only add external metadata ref if IDs exist