Consider adding a bin that avoids resizes
Here is a prototype of the idea: http://meyerweb.com/eric/thoughts/2012/05/15/defining-ch/
Some irc discussion:
- Would be good to move this just to a grid+basesize and don't change properties in measure
- Would be good to support units other than px here, in particular font-dependent ones like em or ch
- Would be good to support ch in css