YaPiG 0.92.1b Released! && 08x->0.9x Upgrade doc

Yesterday, it was reported a very heavy problem related to yapig's security. Now, it is already solved. There was an install.php bug that allowed reinstalling to anyuser. Users using any 0.9x (including 0.92b stable) must update or remove install.php on their gallery.

Upgrading from 0.8x to 0.9x documentation available here:
http://yapig.sourceforge.net/doc/upgrade.html