Fix one major bug in updates and one small HTML formatting bug; also add YEAR to timestamps 

Discovered a major bug in the automated rules update code in the snort_check_for_rule_updates.php file.  The section where the rules files pulled from the 'rulesets' section of the config.xml are tested to make sure they exist was not preprending the fully-qualified path to the rules directory onto the filenames.  This causes no rules to be loaded from the 'rulesets' setting in config.xml because the filenames always fail the "file_exists()" test.

Added an additional configuration parameter to the snort.conf generation function in snort.inc so that log timestamps have the YEAR included.  This parameter is "config show_year".

Finally, added the correct CSS class to a table cell in the snort_rules.php file.  There was a typo where the class was "list" and it should be "listt".