Reading old Graph partition code

* Completed Gibbs sampler generic simple code; should be working

* Minor fixes throughout the code

* Detected a bug in the Message Passing code for FGs; specifically, when a Potential node sends a message. The product of the messages is wrong in the second phase (when messages come back from the root). This is because the whole product of messages is used, and we need to remove from that product the message of the Node we are sending to. Needs to be fixed (urgent)

* Read the old code partitioning a Graph into tree for Rao-Blackwellisation (code dating back to Summer 2004). Code base is very ugly (I really code better now, which is a good thing to see :-), but understandable. Basically, we are doing a partition based on choosing the node with the lowest connectivity (equals are resolved in favor of the latest node "selected"). We have a backtrack of depth 1, if we are going to encounter a "dead-end" (previously called a full-looping vertex, but the terminology needs to be changed). More on this algorithm soon...

* Started a code clean-up (cosmetic changes), on every file.

-> fix the MP bug;

-> continue the code clean up;

-> think about the possible implementation of the old Partitioning code