Improve concurrency, CPU peaks, block state recovery.

 * Attempt to address freak lockups by just locking more things.
   (and add option to stop printing so that kill -QUIT generates
    stack traces).
 * shuffle order of testing to avoid testing the GOOD/WAS_GOODs all
   at once.
 * Move settings to memdatastore.settings to allow for deleting
   blocks/block store.