Changes

I should also add: there's a set of code for bold math (text and symbols) in [http://www.ntg.nl/pipermail/ntg-context/2004/005314.html this message to the ConTeXt mailing list] and [http://www.ntg.nl/pipermail/ntg-context/2004/005315.html its followup here]. This matter is also discussed, perhaps more thoroughly, in [http[magazine://www.pragma-ade.com/general/magazines/mag-0005.pdf |ConTeXt Magazine issue #5]].