Updating the readme.
Giving the system the capacity to remove extra copies of a key from somewhere it doesn't belong.
 * DropAction takes a filename, and drops the file if he thinks he should.
 * still need some persistent storage of totalCopies/numMirrors for each file.
 * still need a strategy for how this works when driven from merkle-land.
Fix an exciting race condition hang in load_test.