Fixed some Venus Pitcher pregnancy issues.

There's also a report along the lines of these scenes increasing butt looseness, but I can't see anything that would be causing it. Trying to get my hands on a save to see for myself.
Fixed a method used to retrieve stats from the StatTrack class that was causing one of the Venus Pitcher birth scenes to crash.
Fixes some more issues with StatTracking so that it actually serializes properly. Oops.