Added Shadowdark RPG version

This might sound like deja-vu, but I've published another alternate version of the booklet - this time designed for use with Shadowdark RPG. The biggest difference again is in the monsters section, where I modified the stat blocks to fit Shadowdark formatting and other rules differences versus Knave 2e. Throughout, I also added references to XP rewards and modified any out of place terms like "coins" instead of "gold", "Magic-User" instead of "wizard", or for example "succeed a DEX skill check" instead of "DC 12 DEX".

I also removed a couple extra or missing spaces I caught in the original version.