added __init__ to tests and corrected replaced assertOrderedDictEqual with assertEqual
Merge pull request #153 from ankurankan/dev

added __init__ to tests and corrected replaced assertOrderedDictEqual wi...
correction in init method of RuleCPD. Earlier it was setting the value of rules to None instead of empty dict when no argument was given
adds method to verify the rules given by user in init and add_rules methods [refs #140]
Minor correction in docstring and adds a TODO
more efficient _verify method. Replaced two loops with itertools.combinations and fixed return statement (Earlier was returning just True due to which other function (init and add_rules) trying to access the 0th index of the returned value were throwing error.
tests for RuleCPD class
Merge pull request #157 from ankurankan/dev

Implementation of RuleCPD and tests
corrected local_independencies method. Earlier it was showing duplicate variable in event1 and event2 [fixes #158]
adds __str__ and __repr__ methods for Independencies and IndependenceAssertion class
adds __str__ and __repr__ methods for Independencies and IndependenceAssertion class [fixes #129]
Merge branch 'dev' of https://github.com/ankurankan/pgmpy into dev
Merge pull request #160 from ankurankan/dev

Fixes #129 and #158
Merge branch 'dev' of https://github.com/pgmpy/pgmpy into dev
Pulled changes with upstream (the original pgmpy repo)