use naturaltime for elapsed times (resolves #229)
Merge commit 'fd0ab29dfcfc263be686c8351f4dc5880e3e1b9b' into template-cleanup

Conflicts:
	helpdesk/templates/helpdesk/dashboard.html
	helpdesk/templates/helpdesk/kb_category.html
	helpdesk/templates/helpdesk/ticket_desc_table.html