Chunked mempools, a first verdict

A fair bit of cleanup remains before this can get committed to HEAD.

* src/MemPoolStats.c is a mixture of different things, while the name
suggests it should be statistics.. probably much of the non-statistics
things there should be moved to lib/MemPools.c

* The namespace used is way to large. lib/MemPools.c (after a initial
cleanup) export 25 symbols, plus 7 from src/MemPoolsStat.c. This is way
more than should be required. (the old MemPool.c exported 16 symbols,
which already was way to much for a memory pool allocator).

* The whole concept of how/where statistics is kept and retreived is
messy and needs to be thought over and better designed.

--
Henrik