A simple, hackish tool for locating resource clusters in Minecraft maps.

Please note that as of this commit, only the new Anvil file format is
supported which means that if you want to use this tool with Minecraft versions
older than 12w07a (that is, 1.1 and earlier) you will have to use a pre-0.1
version.

You need a somewhat recent version (anything from 7.x will do the trick) of GHC
in order to build it, along with the libraries binary and data-binary-ieee754.

To use it, simply run it with the (x, z) coordinates and map directory you want
to search and, optionally, the type of block you wish to find. If you don't
specify a block type, it's assumed that you're looking for diamonds, and only
the layers of the map where diamonds can be found are examined. If you specify
a preset, such as "gold" or "clay," only the layers where such blocks may be
found are examined. If you specify a numeric block ID, the entire bottom half
of the map will be examined.

A few examples:

This will find all clusters of diamonds between (-100,0,-100) and (100,20,100)
in the save called World1:
./rfinder -100 -100 100 100 ~/.minecraft/saves/World1

Locate all clay in the rectangle (100, 0, 200) (250, 64, 500):
./rfinder 100 200 250 500 ~/.minecraft/saves/World1 clay

Locate all obsidian in the rectangle (0, 0, 0) (100, 64, 100):
./rfinder 0 0 100 100 ~/.minecraft/saves/World1 49