JTA belief propagation, functioning but unusably slow!
Improvements to LabelledTensor
Added FactorGraphViewer
LabelledTensorSpecs
Fixed junction tree bugs (hopefully)
Cleaning up Junction Tree / LabelledTensor stuff, adding docs, merge
Merge remote-tracking branch 'remotes/origin/dev' into JTA

Conflicts:
	wolfe-core/src/main/scala/ml/wolfe/BeliefPropagation.scala
	wolfe-core/src/main/scala/ml/wolfe/FactorGraph.scala
	wolfe-core/src/main/scala/ml/wolfe/fg/Var.scala