Partial analyze preg to js

The actual guts of the womb loop works really well in JS, and we can standardize it between slave and player (they had started to diverge slightly).

My ulterior motive? I would like to use this scan code to allow cheat editting fetuses, the same way I'm stealing deduping code from starting girls for js cheat.

edit: I should add some of analyze is dumb as hell still. Like, links that try to update a temp variable before refreshing the passage, dumb.