Update .travis.yml
Update .travis.yml
Merge pull request #127 from ankurankan/dev

replace parse method of etree with ElementTree so that it supports cElementTree also
Merge pull request #132 from ankurankan/dev

Adds method local_independencies to BayesianNetwork class
Merge pull request #134 from ankurankan/dev

adds moral_graph method
Merge pull request #136 from ankurankan/dev

__hash__ method for factor class and reorder import statements
Merge pull request #138 from ankurankan/dev

TreeCPD class
Merge pull request #146 from ankurankan/dev

Tests and minor correction in TreeCPD
removed assertOrdedDictEqual function
minor correction in tests
modifications in pgmpy.Factor.__init__.py to import TreeCPD, TabularCPD and JointProbabilityDistribution
modifications in docs to show TabularCPD, TreeCPD and JointProbabilityDistribution
removed redundant module from api.rst
__init__.py modified to include readwrite module
removed redudant __all__ from all the readwrite modules
modified __init__.py to include all the readwrite classes and methods
modified api.rst to show readwrite module documentation
Merge pull request #149 from abinashpanda/dev

Updated documentation for new classes and methods
added sphinx to readthedocs-requirement-pip.txt
Merge pull request #150 from abinashpanda/dev

added sphinx to readthedocs-requirement-pip.txt