Seed Finder Mod

First version of my seed finding mod. It's my first mod so it's likely to be a little rough around the edges.

Known Issues:

• Default overworld retains the last seed that was loaded, so if you go flying around it you'll see some pretty obvious chunk boundaries.
• The dimension you were in when you left the world isn't the dimension you'll be in when you reload it. Just use /findseed load to get back to whatever seed you want.