This commit coverts everything in the codebase to use the new
users_order_by_sql function when sorting lists of users. More details in
the bug.
Note that this does not change places where users are displayed in a
sortable table, and the sort order comes from the table.
Major tasks undertaken in this patch:
* New format_text argument, overflowdiv.
* New page layout Report.
* Review of all format_text calls.
* Added support for the report layout to all themes.
* Changed forum post display from tables to divs.