RAII port of kstring_t from klib.
kmp::Pool is a simple memory pool which reuses pointers which have already been allocated.
Part of kbtree has been ported. There are some issues with memory management, and it is not ready for use.
klib is Copyright (c) by Attractive Chaos attractor@live.co.uk, which this work is a simple port of. I release it in the hope that it will be useful.