Changes
New section: missing items in the texshow web.
* \setuphead style vs textstyle/numberstyle setting (from nikolai): It seems that one can't retrieve the textstyle or numberstyle settings from a \setuphead when using \placeheadnumber
* enco-ec.tex: \textmu should be upright, even in the ec encoding
'''Missing items in texshow web''':
* <cmd>definelayer</cmd>, <cmd>setuplayer</cmd>
* <cmd>definecolumnset</cmd>, <cmd>definecolumnsetspan</cmd>
* <cmd>setmode</cmd>, <cmd>doifmode</cmd>, <cmd>doifmodeelse</cmd>
* <cmd>uniqueMPgraphics</cmd>, ...