Revision 875

DataSources added to modelframe/EsysXML, and tests to run_xml.py. Currently does not actually handle data 
sources, 
just references. Functionality is in progress. 

EsysXML format (URI can be a local file reference, or a remote reference such as an ftp site, fileformat 
is currently any string descriptor, such as finleyMesh or gmtdata):
 <Parameter type="DataSource">
                        <Name>
                                uritest
                        </Name>
                        <Value>
                                <DataSource>
                                        <URI>
                                                somelocalfile.txt
                                        </URI>
                                        <FileFormat>
                                                text
                                        </FileFormat>
                                </DataSource>
                        </Value>
                </Parameter>