Completed Unsafe Exit Teleportation

Completed the code in yCoordHelper for choosing a point to drop the
player when using a Transdimensional Trapdoor. Made changes to
DDTeleporter so that the player can be dropped at the specific point we
want. This needs further testing, though, since I'm not completely sure
it's working right.
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Minor Change

Removed unused import
Minor Fix in BlockDimWall

Fixed an issue that skyboy had pointed out long ago about us using
ItemBlock.itemID as a block ID instead of ItemBlock.getBlockID(). That's
potentially hazardous because that function was introduced specifically
so mods could override it and decouple item IDs from block IDs.
Progress on New Save Format

Integrated the base code for our new save format. It still needs more
work but at least some substance is there. Ignore the file not found
messages that come up when trying to save the world's data - since we're
not actually writing files, an exception occurs when we some later code
tries to move non-existent save files.

Also moved the FileFilter functionality out of DungeonHelper and into
its own class, FileFilters, since it's finally needed more broadly.
Merge remote-tracking branch 'upstream/DevBranch' into rewrite
Deletes IItemDimDoor

Doesn't seem like we need it... and it's in the wrong package. Respect
the packages! õ_Õ
Merge pull request #88 from SenseiKiwi/rewrite

Progress on the New Save Format and Minor Fixes