First hack at the random flooding code.  It technically works, but it
may exhaust memory quite quickly.  Issue seems to be that I don't
check the contents of the closed list during the flooding step, so you
get ever increasing frontier sizes.
Added local (map based) closed lists to the random flooding code.
Improves performance on the rovers test instance.

Probably want to go back and replace the map with a real hashtable at
some point.  We may also want to return the map from the from flood at
some point, in order to do the learning.
Flooding step now returns it's local closed list.
Changed my mind -- rather than handing back the closed list, I hand
back a vector of frontier vectors -- it's basically every node
included in the flooding step, separated by layers in the flooding
stage.

My guess is this is the information we'll want for learning.  At the
very least, we'll want the last layer, if not all internal layers.
removed debugging printfs
Merge pull request #4 from jordanthayer/master

Fixed minor issues in random flooding