Started work on Gaussian Bayesian Networks
Re-org with some common graph stuff moved to graph.py
Need a better solution for matrixes....
Added pure python Matrix module for folk who dont have numpy.
WIP Conditional to Joint...
Added small linear algebra module for non-Numpy installs.
Added tests for linear algebra.
Added bayesian/gaussian_bayesian_network.py
Inverse of matrix in linear algebra module added.
Added more tests.
Added tests for conditional_to_joint.
Added tests for conditional_to_joint.
WIP converting previous functions to Matrix instances.
Added tests for river example.
Added CovarianceMatrix class which tracks variable names internally.
Added class constructor methods for MeansVector and CovarianceMatrix classes.
Finished first draft of results API for GBNs.
Small pep8 fixes.