Bnlearn

* Unit tests added!
* bnlearn.print_DAG changed into bnlearn.print_CPD
* output of bnlearn.parameter_learning is a dict containing the model and adjmat.

Documentation link changed: https://erdogant.github.io/bnlearn

Added new functionality to bnlearn:
* make_DAG()
* print_DAG()
* adjmat2vec()
* vec2adjmat()

* Documentation: https://erdogant.github.io/bnlearn/

* Docstring improvements
* Code cleaning
* Compatible with latest version of pgmpy (v0.1.10)
* black_list and white_list incorporated for structure learning
* Bugfix for BDueScore

* structure_learning() -> structure_learning.fit()
* parameter_learning() -> parameter_learning.fit()
* inference() -> inference.fit()
* Simplified input for plot().
* Code refactoring
* Code cleaning
* Doc strings added

* Function name for loading example changed to import_DAG
* reading example dataframe with sprinkler data added by bnlearn.import_example()
* Verbosity fix