add LegacyMetadataDO for working with old-style objects with METS datastreams. Note: all new objects should be created with the newer style, not this one.
fix class for LegacyMetadataDO
add a thumbnail datastream to MasterImage so we can more easily work with thumbnails
add PDFLegacy & BlobLegacy models
Merge branch 'master' of https://github.com/Brown-University-Library/bdrcmodels
add Blob
add undetermined model; add get_cmodel_info, which is used by the API to create new objects
add jp2 & jpg models (standalone, not extending MasterImage
Merge branch 'master' of https://github.com/Brown-University-Library/bdrcmodels