bugfix: `test_expectedResults` args in index script
bugfix: missing import `ObjectDoesNotExistException`
refactor database index script

Refactored database index in order to allow background indexing to be
start at a named stage, e.g. to finalize after manual testing of
offline indexes. Command is now one of:

    $ python index.py live

or

    $ python index.py background

Testing and finalizing in background mode can also be skipped. To index a
subset of data without failing tests use `--no-tests`; to keep new indexes
offline for further manual testing use `--no-finalize`
bugfix: tolerate forward slash in identifiers
bugfix: search within collection form attributes
remove index select for search within collection