Reorganized Schematics

Removed untagged schematics and replaced them with the tagged
schematics. Moved two schematics that said NOT DONE into a "wip"
subfolder. Moved somethingBroke into a "core" subfolder. All remaining
schematics were placed in a "ruins" subfolder in preparation for the new
dungeon packs system. I did my best to ensure that all of the old
schematics had been copied and tagged, but it's possible I might have
missed one or two. I also copied in my new dungeons. This commit
temporarily breaks the mod until the new file names and locations are
referenced.
Merge remote-tracking branch 'upstream/master'
Added Stairs to Core Schematics

Copied simpleStairsUp and simpleStairsDown into the core schematics
folder. It's likely they'll be useful for testing in the future. To be
clear, I didn't remove them from the regular "ruins" folder, just copied
them.
Improvements to DungeonHelper

Removed hardcoded references to all our internal dungeons. The code will
be replaced by reading from a list in the next commit. Renamed
customDungeons to untaggedDungeons and removed registration of tagged
dungeons into that list. Now all tagged dungeons (custom and internal)
are listed in registeredDungeons. Fixed the comparator used to sort
dungeon names so that it sorts them case insensitively.
Fixed CommandCreateDungeonRift

Forgot to fix a reference to DungeonHelper in CommandCreateDungeonRift
during the last commit. Made some further improvements to DungeonHelper
to avoid exposing internal variables.
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.
Merge pull request #61 from SenseiKiwi/master

Progress to Next Update