Yo-yoify (or something) critical render paths

[bcomnes]

Yo-yoify really speeds things up by replacing slow bel calls to really fast createElement calls. This is mainly important for the infinity scroller since we still have some performance hiccups on list re-renders.

I don't want to introduce a built step. Either replace bel usage in these render paths with built in calls to createElement, or create a bel memoizer function that does what yoyo-ify basically does on runtime.