[1.4] Remove/migrate throwing items

[The-Voidwalker]

The throwing class doesn't exist in 1.4, steps should be taken to modify any thrower class items so that this isn't a problem any more.

Current plan:

• Convert Pointy Pocket to accessory that adds throwing knives on weapon use.
• Convert Scroll of Throwing to accessory that adds piercing, gravity immune, throwing knives (or other projectiles) on weapon use.
• Remove throwing stats from all items.