Fixes bug 5232: Shelfname won't display on high-numbered lists

Fixes bug 5232: Shelfname won't display on high-numbered lists

This bugfix adds an explicit GetShelf for the specific shelfnumber when viewing that individual shelfnumber.  This captures the
shelfname, which was originally pulled from shelflist->{$shelfnumber}, which may not have been populated if the List in question was
beyond the 20th private or public list in the system.

Also adds a more explicit sort: the sort from the CGI takes top priority, then it falls back to the default sort for the list, and
ultimate falls to 'title' if neither CGI nor default sort exist.

Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com>
Signed-off-by: Nicole Engard <nengard@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>