Pull request for: Changes for #57

I've changed a bit the nosetests command to also generate an xml export. So I added:
`--with-xunit --xunit-file=ckanext-hdx_theme/ckanext/hdx_theme/tests/nose_results.xml ` and 
`-with-xunit --xunit-file=ckanext-metadata_fields/ckanext/metadata_fields/tests/nose_results.xml `.

This saves the report inside the git project (inside each extension). If you prefer not to pollute the project, please just change the path for *--xunit-file*. I anyway added *nose_results.xml* to *.gitignore* on the ckan project.