Superscript for scientific notation

[welchr]

Look into how we might go about allowing the exponent from the logtoscinotation transformation to be returned in superscript, for example with <sup>.

One hitch to this currently is the htmlescape transformation that is applied currently after logtoscinotation. Some followup is needed to check if there are other places where logtoscinotation is used, and returning HTML would break something that expects text-only.