Add absolute accuracy

[jtwalsh0]

Webapp should plot predicted versus true probabilities. Bin predicted probabilities, e.g. all between .4 and .5 and see if the average is ~.45. I'm looking for something like this.

We can also get an AUC score for this, but unlike ROC, the best is 0.5 and the worst is 1.0 or 0.0. We should generate this AUC score for every model and store it in the results.evaluations table