removing DP from PO event types

[bdilday]

The model specification says that for modeling putouts, only non-double-play data are used. It is unclear if this means events that did result in a double play, or events that could result in a double play.

[bachlaw]

Currently there are binomial models for single putouts to positions 1 through 9, and then models for double-plays where the first putout was to positions 2 through 6.