Attach containers to existing ones refs #6579

Physical containers being imported via EAD will now check to see if
there's an existing physical container attached to the collection,
and use that instead of duplicating now.
Enhance statistics output for import:bulk #7108
Fix class name
Add identifier sorting where relevant, fixes #6308

Squashed commit of the following:

commit bb37ea0484ec2a0209d99dd7f0b20905df56ea39
Author: Kehan Harman <kehan@gaiaresources.com.au>
Date:   Wed Feb 12 17:35:12 2014 +0800

    Fix problem error with actor browsing - use addSort so we can then add a
    secondary sort by 'title'

commit 9a440a3a3a0f8114161163e33b63b24dde72cd3b
Author: Kehan Harman <kehan@gaiaresources.com.au>
Date:   Wed Feb 12 11:51:08 2014 +0800

    Adds preference and default sorting by identifier. Adds the sort by
    identifier to the relevant browse forms.
    https://projects.artefactual.com/issues/6308

    Conflicts:
    	plugins/qtAccessionPlugin/modules/accession/actions/browseAction.class.php
Fix verbose flag in import:bulk #7145