Data science 20141007 rc

First pass at the data science exercise.

-simple json file loading
-Dataset contains all results from file, helper methods for calculations, uses ABAnalyzer class to calculate probability
-main.rb used to display results (sample size, conversions, percentages with error ranges, and confidence level)
Do you really need results to be accessible? or should dataset be a closed wrapper? Maybe you do want it accessible. But if you wanted to isolate the data, you can remove the attr_accessor and then refer to the result via @result instead of just calling 'result' which is using the magic method created by attr_accessor :result