Changed NPC pickup logic so only weapons marked as "NPC usable" can be picked up by NPCs. This can be overridden with mcitem_npc_pickup 2

Added several suggestions/requests.
* mcitem_manualpickup: Make players press E to pickup items
* mcitem_autoequip: Configure autoswitching for the items, with respect (or not) to the default autoswitching system
* Added NPC support, with convars mcitem_npc_deathdrop and mcitem_npc_pickup
Thanks for the thumbs/subscriptions, it's awesome seeing this on the front page!

Fixed an issue where items wouldn't move correctly on a dedicated server.