Backpack state is now tracked through the inventory.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2603 86ba831e-150c-0410-ab35-e06eaae15ed9
Remove obsolete backpack item drops for players that were supposed to take effect during -trideath mode; may replace with something simpler such as an active weapon drop, to repurpose the DM_PLAYERDROP flag.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2604 86ba831e-150c-0410-ab35-e06eaae15ed9