Better consensus update

Added fam_consensus_update, and made b_consensus_update use it.
Comments.
Updates to b/bi

Added b_add_bi. bi’s now stored in an extensible pointer list within b
(as is already the case with fams in bi and raws in fam).

Changed b constructor to initialize and store the list of raws within b.
Added b_init

b_init sets (or resets) the clustering object into one cluster/one
family.

Bugs.