Add cl_bayes.py to src

[CCLynch]

Current Work:

cl_bayes.py trains simple LDA, QDA, and GaussianNB classifiers then plots their decision boundaries, ROC and DET curves.

Further work:

I haven't yet updated the markdown doc for the bayesian classifiers, and I want to add confusion matrices to my script.

[sophiacofone]

Looks good to me

[ZongyuWu97]

looks good