LP#1549505: Add ability to set default sorter via global flag

LP#1549505: Add ability to set default sorter via global flag

In addition, support for sorting by ascending popularity remains
in the back end, however, since if one's configured badges such
that almost every record has a badge score, that sort order could
be useful for examining the long tail of the collection.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>