Until now, the black, white, blue and brown dyes doubled as squid ink sac,
bone meal, lapis lazuli and cocoa beans. Since these latter items have all
been given their own craftitem registration, the missing dyes can finally
be added in their own right.
* Add `"mcl_dye:black"` and its crafting recipe.
* Add `"mcl_dye:white"` and its crafting recipe.
* Add `"mcl_dye:blue"` and its crafting recipe.
* Add `"mcl_dye:brown"` and its crafting recipe.
* Remove aliases for white and brown dyes.
* Rename dye item images to be conforming to mineclone naming standards.
* Minor simplifications of mcl_dye/init.lua.