Fix for 6426 - messaging not showing on patron categories

Fix for 6426 - messaging not showing on patron categories

T:T variable name problems were causing the problem.

I used this opportunity to change the way the data is
output: Now the messaging preferences are only output
if there is a current setting.

Also corrected the js table sorter configuration for
the right columns and moved the template-based table
row striping to the tablesorter plugin config.

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