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.