There's no point free-ing memory when the kernel can do it for us.
Just reuse the already allocated memory to hold lines.
Thanks Truls Becken for pointing this out.
It actually makes the binaries smaller, the code easier to read
(gems like "val == true", "val == false" are gone) and actually
predictable in the sense of that we actually know what we're
working with (one bitwise operator was quite adventurous and
should now be fixed).
This is also more consistent with the other suckless projects
around which don't use boolean types.
