Add .thead_right and .thead_left classes

When you have two columns with two .theads the CSS3 border radius rounds the inner corners which is not desirable.
Add 24 hour lock to admin log

To prevent recent actions being wiped by unauthorized people, add a lock to the admin log which prevents logs less than 24 hours old from being pruned.
Add 24 hour lock to moderator log

To prevent recent actions being wiped by unauthorized people, add a lock to the admin log which prevents logs less than 24 hours old from being pruned.
Use relative time for moderator logs
Remove deprecated <font> tag
Update attachtype images