Re: dom3 interfaces build

The Xerces jar that contains L2 interface definitions is on the compile
classpath by default since it is included with Ant.  Since the L3 interfaces
in the version of Xerces that is distributed with Ant will lag the most
current working draft, the build file needs to compile the interfaces from
the W3C sources (which it is apparently doing) and prevent the Xerces
sources from being referenced (which it probably isn't doing).  I'll add it
to the list of things for me to look at this weekend/