`<input>` and  `<select>` sizing update

Restores `font-size` and more to the `<select>` element while also
changing from `min-height` to `height` for input sizing.

Fixes #8520 as opened by @ShaunR (would've merged that PR but I moved
everything around right before).
Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip