Merge pull request #2 from TuftsUniversity/ttfixes

Jira DRINGEST-356 typo fixes
DCA 1038. Committing the changes to allow multiclass objects from a spreadsheet, and also fine tuning those changes so that stabilization is only included for digital objects.
Merge pull request #3 from TuftsUniversity/dca1038-multiclass_objects

DCA 1038. Committing the changes to allow multiclass objects from a spre...
Refs #182 - Adding support for an "action" attribute on <classes> sub-elements in import files, and generally improving the way that existing classes are treated during batch-updates.
Refs #192 - Teaching the digital object import method that the salient field of file extensions is `extension`, not `name`.
Refs #185 - Computation of derived date_to fields will now consider the date_from fields of children whose date_to fields are set to NULL.
Merge pull request #4 from TuftsUniversity/182-class_batchupdate_bugfix

improving the way that existing classes are treated during batch-updates
Fixes #192.
Merge pull request #6 from TuftsUniversity/185-handling_null_date_to

Fixes #185 -- running repair_derived_fields now.
created export template for collection records to ingest finding aids