0.1.6

• fixed #44, #40.
• New class hierarchy for Models:
  • the main interface is Model,
  • the graphical models now implements the GraphicalModel interface,
  • basic Directed Acyclic Graph is DAGModel,
  • the BayesianNetwork class is now a specialized case of DAGModel,
• Added Join Tree and Belief Propagation algorithms for BayesianFactor-based models.
• Added algorithms for entropy of Bayesian and Credal networks.
• General code cleanup (mainly code style).
• Removed main methods from the library and moved to separate unit test classes.
• Updated tests and removed old experiments.
• Removed examples relative to Adaptive project.
• Updated tutorials.