Bug fixes for MIS module


**Functionalities implemented:**

**1) Fix NoReverseMatch url issue - 'view_articles' [added key 'group_id' to context_variables dictionary]**
   - Except person's sub-types' registartion, while editing all other registration modules the following error was thrown:

     - ```NoReverseMatch: Reverse for 'view_articles' with arguments '('',)' and keyword arguments '{}' not found. 1 pattern(s) tried: ['(?P<group_id>[^/]+)/ajax/view_articles/']```
     
   - This error will come only in case of rendering template(s) which include(s) "templates/ndf/add_editor.html" template-file.
   
   - This is due to recent merge of pull request i.e., "Bib_App". This merge includes several changes in "templates/ndf/add_editor.html" template-file.
   
     - One was inclusion of a ajax call making use of following url: ```{% url 'view_articles' group_id %}```
     
     - Here, group_id is passed as an argument; and if you haven't passed this from your views, then you will also end up with the above specified error!
     
   - Files modified:
   
     1) views/mis.py
     
     2) views/event.py
     
        - MIS collection list updated based on logged-in user's agency-type
        
        - Code updated for parsing template data
        
     3) templatetags/ndf_tags.py
     
**2) Templates updated**

   1) templates/ndf/student_create_edit.html
   
      - DOB (Date of Birth) date-field widget updated:
      
        - lowerYearLimit: Changed from (currentYear-80) to (currentYear-30)
        
        - upperYearLimit: Changed from (currentYear) to (currentYear-14)
        
   2) templates/ndf/event_create_edit.html
   
      - Updated tabs navigation using next & previous buttons
      
      - Widget updated for start_time and end_time: Instead of jquery's datepicker() function, using jquery-ui-timepicker-addon's datetimepicker() function.
      
   3) templates/ndf/person_create_edit.html
   
      - Submit button's updates:
      
        - Jquery's on-click function call to catch dynamically added submit button's event
        
        - Label toggles(Register/Update) based on whether it's a new node or already existing one!
      
   4) templates/ndf/html_field_widget.html
   
      - Condition modified: If and only if editable field's value exists, then only apply readonly property!
     
   5) templates/ndf/location_widget.html
   
      - 'content' class removed from reveal-modal used for displaying map (after consulting from Kedar)
     
        - As it was not making any sense where it's declared
     
        - Reason for removal: Causing problem in finding no. of tabs in MIS-editing templates as for tabs-content-divs' this class is defined usually