Implementated a common template for editing and displaying content.

(1) New following files/folders added:
     
    - templates/ndf/display_page.html
    - templates/ndf/edit_content.html
    - templates/ndf/display_content.html
  
    - templatetags/ndf_tags.py
    
    - "mathjax" folder added to (gnowsys-ndf/gnowsys_ndf/ndf/static/)
  
(2) Urls' file (gnowsys-ndf/gnowsys_ndf/settings.py) restructured.

(3) New 'Views' folder created to store following views (gnowsys-ndf/gnowsys_ndf/ndf/views/):

    - home.py
    - wikipage.py
    - doc.py
    - ajax-views.py
  
* NOTE: When HTML content is refreshed after editing through org-editor on a wikipage, Mathematical equations are not shown propperly. This is because the mathjax script doesn't gets executed after the ajax call (inside "templates/ndf/edit_content.html" file) is made.