#Issue 6: MF example stub; #Issue 69: factor and node labels spec stub
Issue #69: nodes and factors can get a label that is displayed when printing
Merge remote-tracking branch 'origin/dev' into dev

Conflicts:
	wolfe-core/src/main/scala/ml/wolfe/FactorGraph.scala
	wolfe-core/src/main/scala/ml/wolfe/MaxProduct.scala
	wolfe-core/src/main/scala/ml/wolfe/macros/MetaAtomicStructures.scala
Merge remote-tracking branch 'origin/dev' into dev
added wolfe nlp subproject
fixed notation in factor graph spec