Cave Overhaul

hotfix

1.3.8 changelog:

• added mod menu support via cloth config
• mod menu and cloth config are now soft dependencies (required to compile, optional for client/server)
• removed "aquifer patch" and "flat river" options from config. these options are obsolete as their functionality are now deeply integrated into the mod
• added "vertical cave stretch" to config. caves are vertically stretched by a factor of 2 by default and i'd like to experiment with this value, as it might be too high.