[DAS2] per-database MAINTAINER

[Andrew Dalke]

Based on Andreas Prlic's work with the DAS2 registry I've
added a new MAINTAINER element to the SOURCE/VERSION part
of the SOURCES document.

I've updated das/das2/scratch/sources4.xml to have an
example.  It looks something like this

<?xml version="1.0" encoding="UTF-8"?>
<SOURCES
     xmlns="http://www.biodas.org/ns/das/genome/2.00"
     xml:base="http://dev.wormbase.org/das/genome/">

   <MAINTAINER email="someone at EBI" />

   <SOURCE id="volvox" title="Mr. Volvox" taxid="3066" 
xml:base="/DAS2/GENOME/">

     <VERSION id="volvox/b1" title="Build 1, October 2002"
            created="2002-10-15" modified="2002-10-25T09:56:23">

       <MAINTAINER name="Fred, down the hall" />
    </VERSION>
   </SOURCE>
</SOURCES>


The idea is that the database maintainer can be different
than the server maintainer.

On the other hand addition, if the SOURCES/SOURCE/VERSION/MAINTAINER
is not present then clients may assume that the database
maintainer is the same as the SOURCES/MAINTAINER

The maintainer elements are both optional.

					Andrew
					dalke at dalkescientific.com