Tidy up "system_usermanager.php" XHTML

Add CDATA sections to SCRIPT tags
Close INPUT, IMG and BR tags
Deprecate the ampersand in ANCHOR tags
Remove the NAME paramenter from TR tags
Moved NOWRAP into class statement
Move TFOOT between THEAD and TBODY, this is a "quirck" of HTML
Merge pull request #539 from ExolonDX/branch_04

Tidy up "system_usermanager.php" XHTML