New scripts

[Frank Ellermann]

Doug Ewell wrote:

> add code elements for "Mathematical notation" and "Symbols." 
> Section 3.4 says they must be added to the Registry, no cherry-picking 
> allowed, and that seems fine in principle, but these two are at least as 
> irrelevant to tagging of natural-language text as are the region subtags 
> 'AQ' and 'BV', or the language subtags 'mis' and 'und'.

Indeed, Zmth and Zsym are rather odd.  If that's possible, what was the
problem with IPA and UPA ?  

 Frank