Added simple conflict handling for enchantment id

-Game will still crash if a free enchantment slot can't be found
-Also added a couple restart flags
Centralized item handling in BattlegearUtils

-Should be backward compatible
Added general sensibility command for ...

WeaponRegistry behavior, allowing greater control
-Should be backward compatible with addons
Added helper item init from IMCMessage NBT
Added default sensitivities to WeaponRegistry and

command locals
-Also out-sourced utility classes into the api
Fixed special action