implement common metrics like wOBA, FIP, etc.

[beanumber]

We probably won't be able to do UZR, but we should try to do as many as we can of the metrics that are commonly used to compute fWAR, rWAR, WARP, etc.

[beanumber]

I'm not sure how possible this is. Does someone else want to take this on?

To be clear, the goal would be to write a function like:

fWAR(MLBAM2013)

that would compute fWAR.

The collection of pre-computed WAR totals has been moved to openWARData