Implemented one click Edit for page

* Templates added/removed:
 - edit_node_details.html : This template provides view/edit action for common fields of Node class.
 - display_page.html : This template deleted!

 - edit_page.html : This template added that replaces display_page.html, and includes edit_node_details in addition to already included templates (edit_collection.html and edit_content.html)

* Views & Urls modofied:
 - ajax-views.py : Both edit_content and edit_collection view functions deleted! 
 - ndf/urls.py : And thus, both ajax-views related urls also deleted!

 - page.py, file.py, and group.py : Their first view updated i.e., you will get list of created documents sorted by last_update field in descending order.