Small fixes: typos and pusher method
description tag text is now enclosed in a CDATA section
Renamed Element.text method to text!, to make sure it is clear that it is not a tag
Renamed Element.available_tags method to available_tags!, to make sure it is clear that it is not a tag
Renamed Element.available_attributes method to available_attributes!, to make sure it is clear that it is not a tag
Renamed Element.to_xml method to to_xml!, to make sure it is clear that it is not a tag
Added method to feed object for pushing to aggregators, and global setting for default aggregators
Extracted validation procedures into a separate file
Special treatment of ess tag
Sending additional environment and request data to aggregators
Commiting a manual merge, after switching origin