mmultiscripts/menclose: ensure that HTMLgetScale is not called before HTMLcreateSpan. Fix Math Processing errors described in issue 362.
Fix Math Processing Error for msubsup/msub/msup element.
mmultiscripts: take into account the <none/> case (probably need a better selection of sscale)
change the order again in menclose.js
Scan mmultiscripts children to find the first element with a spanID, as suggested by Davide.
Merge remote-tracking branch 'fred/issue362' into develop

Resolves issue #362