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