Loads the scaffold from the given XML file.
        
        :param      filename | <str>
        
        :return     <Scaffold> || None

def load(filename):
        """
        Loads the scaffold from the given XML file.
        
        :param      filename | <str>
        
        :return     <Scaffold> || None
        """
        # parse a zipped file
        if zipfile.is_zipfile(filename):
            zfile = zipfile.ZipFile(filename, 'r')
            try:
                xml = ElementTree.fromstring(zfile.read('scaffold.xml'))
            except StandardError:
                logger.exception('Failed to load scaffold: {0}'.format(filename))
                zfile.close()
                return None
            zfile.close()

        # parse a standard xml file
        else:
            try:
                xml = ElementTree.parse(filename).getroot()
            except StandardError:
                logger.exception('Failed to load scaffold: {0}'.format(filename))
                return None

        # generate a scaffold
        scaffold = Scaffold()
        scaffold.setSource(filename)
        scaffold.setName(xml.get('name', 'Missing'))
        scaffold.setGroup(xml.get('group', 'Default'))
        scaffold.setLanguage(xml.get('lang', 'Python'))
        scaffold.setIcon(xml.get('icon', ''))

        # define properties
        xprops = xml.find('properties')
        if xprops is not None:
            for xprop in xprops:
                scaffold.addProperty(Property.fromXml(xprop))

        return scaffold