update to errata document

Hi Thierry,

Because of circumstances beyond our control, OASIS has only just finally 
populated its final errata document URIs for the initial WebCGM 2.0 erratum.

Our REC 2.0 errata document is at:
[0] http://www.w3.org/2006/WebCGM20-errata.html

(Hmmm... why "2006"?  Oh well, it is on the cover page of the REC 2.0 -- I 
see no harm in leaving it as is.)

The only thing that changed on the OASIS side, since March, is that the 
corrected DTD was moved to its final location, and OASIS's symlink of the 
WebCGM 2.0 System Identifier (section 4.2.3) was redefined to point at that 
final location.

That final location is reference [7] in our W3C errata document, and its 
correct value is now:
[7] http://docs.oasis-open.org/webcgm/v2.0/errata/os/webcgm20-20070509.dtd

In addition to changing that, I have done some light editing on the errata 
document, and placed the result at:
[1] 
http://www.w3.org/Graphics/WebCGM/WG/2007/errata-20/webcgm20-errata-20070611.html

If you read the section "WG-approved resolution", you'll see the light 
editing around the corrected URI [7], mostly adjusting status from 
"proposed" to "approved".  You will also notice (elsewhere) that I changed 
various dates to "June 2007", "June 11...", etc.  I'm not sure if that was 
appropriate or not.  You can change them back, if the original March dates 
should remain (the change was purely editorial ... a new URI for the final 
DTD location ... I assume we don't need a new WG resolution.)

Finally, I noted and fixed some oddness in line 9, the Copyright and 
Trademark symbols.

Regards,
-Lofton.