This commit moves a lot of clutter to a directory named 'clutter'!
Removed a silly clutter dependence.
Moved more stuff over to 'clutter'.
Made a new interface for the queue, since now we need to store parent,
child and edge too.
Tests for the queue stuff.
More functions! We are about to switch out the old implementation with
the new implementation.
Minor documentation change.
Changed the implementation of the forward propagation. Currently
trying to track down a mysterious bug.
OK, our new algorithm works, but we are yet to do the region graph
abstraction and stuff. Also, we need to fix a bug in
fernandez_specifying_partition.