Simplified limegen.write.mkBitset
Simplified limegen.write.mkBitset

I was working on the assumption that string.find had the same problem with
null bytes in the search string for non-pattern searches as it's documented to
have in pattern-based searches. As a little experimenting showed, that is *not*
the case, allowing for some simplification of code.

zec/moonlime,zec/moonlime