Improved DungeonHelper

Completed changes so that our code uses registerDungeon() (formerly
registerCustomDungeons() ) to register all dungeons, both bundled with
the mod and custom ones. Made some changes to the code to hide
implementation details from other classes. Also, I had some problems
with old dungeons being mixed into the renamed ones. I had to remove
fallingTNThall from the schematics folder and deleted the WIP folder
because I think we have completed versions of those schematics already.

Some of our dungeons have pre-filled chests and the contents are more
generous than our current loot system (e.g. ruinsO has a prefilled
chest). I'll have to wipe all the chests later.

StevenDimDoors/mod_pocketDim/SchematicLoader.java

@@ -71,7 +71,9 @@ public class SchematicLoader
 				//TODO: In the future, remove this dungeon from the generation lists altogether.
 				//That will have to wait until our code is updated to support that more easily.
 				System.err.println("The dungeon will not be loaded.");
-				dungeon = checkSourceAndLoad(DungeonHelper.instance().defaultBreak.schematicPath);
+				DungeonGenerator defaultError = DungeonHelper.instance().getDefaultErrorDungeon();
+				dimList.get(destDimID).dungeonGenerator = defaultError;
+				dungeon = checkSourceAndLoad(defaultError.schematicPath);
 				dungeon.applyImportFilters(properties);
 			}