Fix regression from #1069 (mathjax/MathJax#3233, mathjax/MathJax#3234)

[dpvc]

This PR fixes a regression introduced in #1069 in which primes are misplaced for \underline{x} and give an error about double superscripts for \overline{x} and similar macros. This was du to not taking the subsupOK property in account for these munder and mover constructs. We add those checks here.

Also, this fixes some non-critical number/boolean issues in the base mappings and macros. It works the way it is, but the types are wrong, so we straighten that out here.

Resolves issue mathjax/MathJax#3233 and mathjax/MathJax#3234.

[zorkow]

Two points:

• The underlying BaseMethods in develop has now changed significantly, so it might be easier to "replay" the changes in a new branch and create a new PR.
• It is also likely that the current changes break some of the tests.

[dpvc]

OK, I have made a new branch and will make a new PR for it, so closing this one.

The tests suggested some additional changes to improve the results, and after that the tests all pass, so don't need modification.