Mainly for ^ for centering:
"%{hi!%}^8s" -> " hi! "
Note we can right bias with the nested modifier!
"%{%{hi!%}^7s%}>8s" -> " hi! "
Also note this does _not_ support fill characters like python's format.
I'm not sure it's tractable with %-modifiers, python's format must get
up to some funky parsing to make this work ("%s<s"?).
I think this also fixed the behavior of left-aligning numbers? Seems we
weren't handling that before.
Christopher Haster
d4a2ce4a4e