Adding factory for Transcript models.
Adds spec for Transcript model.
Merge branch 'development' into add_transcript_datastream
Moves factory for PbcoreDescDoc datastream to spec/factories/datstream/.
Adds some TEI fixtures for testing.
Adds TeiDatastream metadata to Transcript model.
Adds factories and initial tests for TeiDatastream.
Modifies spec for Transcript model.
Merge pull request #602 from afred/add_transcript_datastream

(The fixtures will be used soon.)