parser for proposed 3.0 syntax

I updated OpenXRI (www.openxri.org) to support the current draft 19 of
the proposed XRI 3.0 syntax at
http://wiki.oasis-open.org/xri/XriThree/SyntaxAbnf. The change is that
in this draft xrefs can be used as a subsegment.

I have a simple frontend for the OpenXRI parser at
http://www.testxri.com/tools/XRIInspector3/. For example, you could
input the XRIs we discussed at the last XDI TC call.
+x+y
+x(+y+z)
+x(+y)+z

You can choose between the raw parsing results (a tree of all the ABNF
rules that matched) and a more human readable result.

Markus