POWDER schema bug fix

Changelog 12-Sep-08:
- the IP4 datatype in wdrd.xsd had an extra parentheses in the
xsd:pattern regular expression
- the global attribute definitions in the included wdrp.xsd were causing
popular XML IDEs confusion, namely that they perceived that these
attributes must be qualified (despite the top level default that they
are unqualified). Fixed by moving the definitions locally.
 
The new POWDER schema is available from
http://www.w3.org/2007/05/powder/wdr.xsd
<http://www.w3.org/2007/05/powder/wdr.xsd> 
 
Cheers
Kevin