Collection tab updated - Group-wise collection nodes displayed; Minor changes to urls & collection-edit 


**Functionalities implemented:**

1) **Collection tab updated - Group-wise collection nodes displayed**

   - Files modified:
   
     1) templatetags/ndf_tags
        - get_resource_collection() tag: if-else replaced by mongodb query (including group & member_of based selection)
        
     2) templates/ndf/page_list.html
     3) templates/ndf/file.html
     
2) **Urls updated: MIS and Observation GAPPs**

   - File modified:
   
     1) urls/__init__.py
        - MIS & Observation GAPP's urls moved above 'groupchange' url
        
3) **Radio buttons formatted in Collection-edit tab**

   - File modified:
   
     1) templates/ndf/node_edit_base.html
     
4) **Two images related to ajax loader(/wait) added in static directory**

   - ajax-loader.gif
   - ajax-loader-trans.gif