Fixed modded Block and Item material registration for Bukkit.

Mod items and blocks will register as the following:

1. Mojang's registry auto-assigned ID will be used for material ID's.
2. Material names will no longer use 'XID', instead they will now use the
same name passed to Mojang's registry such as
'BiomesOPlenty:bootsAmethyst'. Any non-valid characters for yml config
files will be replaced with '_'. Names will also be set to uppercase by
default. So the final output of the BOP item above would be
'BIOMESOPLENTY_BOOTSAMETHYST'.

Note: As there are not many mods currently available for 1.7.2, these
settings may change in the near future depending on how everything works
out.