(Needs testing) Weapon/Item reload refactor.

Previously the game methods only handled reloading wielded weapons, when reloading something that is not wielded the game will temporarly remove whatever is the current weapon, wields the item be reloaded and calls the reload function. This did not make sense and caused problems like https://github.com/CleverRaven/Cataclysm-DDA/issues/3284

So what i did is move the heavy lifting to game::reload(char) and game::reload() simply passes the wieldeded weapon to the previous function, along with modifications to make the rest of handle reloading items per item(letter) instead of only reloading the wielded item.