Updated documentation + blocklist location changed

Hi,

first many thanks for providing an update for Minecraft 1.5.

I have made the respective changes to the documentation. I hope I did not forget something. I also added a hint that it may be required to add alpha channels to some minecraft textures in order to work.

The other thing is, that I changed the path where the *.list files are expected. Currently it's the working directory. I changed it to be the image directory specified with -g. I think this is more appropiate for the use in shell scripts where the working directory might be something different.

Cheers,
UniversE