add support for new <Description> tag in AssetGroupConfig
add support for new <Description> tag in SiteConfig
use conditional to match original behavior on description
get the description text and not the element!
refactor group to_xml to use as_xml like sites
Make sure that we don't use a nil description in site or group saves
Merge pull request #70 from gschneider-r7/master

Add support for new Description tag in site and group configs