Bernoulli Naive Bayes: first draft

This is the first draft of the bernoulli naive bayes implementation. It
is missing the Fit function tests and the Predict function.
Merge branch 'master' into feature/naive
Refactoring for base.Instances

Refactored the algorithm to use base.Instances. Rewrote the Fit method
to pre-calculate priors and conditional probabilities.
Finished Fit test for simple cases

Added the logCondProb tests for a simple test case with two classes.
Added Predict function

Added predict function along with its test. Current interface is the
same of the KNN example. In other words, only the class string is
returned from the PredictOne function.
Merge branch 'master' into feature/naive
Removed class prior pre-calculation

Since the number of instances in each class are stored, there is no need
to keep the pre-calculated priors.
Merge branch 'master' into feature/naive
Added package documentation
Merge pull request #59 from tncardoso/feature/naive

Bernoulli Naive Bayes