Two further MathML queries

[Duncan Hothersall <dh@capdm.com>]

Apologies for all the MathML queries. Here are two more, embedded in one 
test file which will run on live.contextgarden.net:

--
\usemodule[mathml]
\setupwhitespace[medium]
\starttext
\TeX{} maths aligns $x$ well.\par
MathML aligns 
\startXMLdata<imath><math><mi>x</mi></math></imath>\stopXMLdata squashed 
to the right.\par
Also:\par
\TeX{} display maths makes text go smaller for fractions inside fractions:
$${{\rm Q}\over{\rm P}}\over{\rm R}$$
I'd like the same to happen for MathML:
\startXMLdata <formula><math><mfrac><mrow>
<mfrac><mrow><mtext>Q</mtext></mrow><mrow><mtext>P</mtext></mrow></mfrac></mrow>
<mrow><mtext>R</mtext></mrow></mfrac></math></formula>\stopXMLdata
\stoptext
--

In summary:

#1 Inline MathML has a wide space before, and no space after.

#2 Display MathML doesn't reduce font size for <mtext> content such as 
fractions within fractions.

I have done a fair bit of source- and archive-surfing on both these but 
no luck. Many thanks for any help.

Duncan