Merge branch 'markov' into issue200
checks for self loops and cycles in TreeCPD
changed representation of multivariable nodes in TreeCPD and improved docs
[refs #200] adds tests for TreeCPD and some improvement in code
[fixes #201] adds tests for TreeCPD
[refs #200] minor changes
[refs #201] tests for TreeCPD
updates TreeCPD tests according to the new representation
[refs #201] tests for multi variable nodes
minor change
changes in to_tabular_cpd method
Merge pull request #206 from ankurankan/issue200

Fixed TreeCPD and RuleCPD issues