Discs Where Discs Shouldn't Be

This update is huge, adding a new sherd, reworking the Copper Whistle into the Ancient Whistle, 4 upgraded versions, and a bunch of other small changes.

• Added functionality for the Melody Sherd using SherdAPI. It is built directly into the mod and does not require an additional download.
• Changed the texture for the Unrefined Disc Core.
• Changed the name and texture for the Copper Whistle, changing it into the Ancient Whistle.
• Added Amethyst, Gold, Diamond, and Emerald Whistles which are crafted in the Smithing table. Each whistle has a unique melody which is played by right-clicking.
• Added a trade for the Wandering Trader, offering an Unrefined Disc Core for Emeralds.
• Reworked a lot of the code for the mod, especially for Loot Tables. This mod should now play well with other mods that modify the Loot Tables for Suspisous Gravel in Trail Ruins.