Bug fixes and minor updates

**Functionalities implemented:**

**1) MetaStudio's icon link (Broken link rectified)**
   - Link was broken: That is, was showing "home" in address-bar but redirecting to user-group
   - It's mainly because link was given as "/home" (trailing backward-slash was missing); and I guess, explicit url was created just to support this which was misguiding altogether
   
   - Files modified:
   
     1) gnowsys_ndf/ndf/templates/ndf/base.html
     2) gnowsys_ndf/ndf/urls/__init__.py
     
**2) Restricting MIS, MIS-PO and Batch GAPP's access to only gstaff members (superuser, creator and admin of the group)**
   - These GAPPs will be shown only in the gapp-iconbar list only when a gstaff member is logged-in.
   - Care also taken to restrict, if someone directly enters' url in the browser.
   
   - Files modified:
   
     1) gnowsys_ndf/ndf/templatetags/ndf_tags.py
          - Following methods updated:
            - ```check_is_gstaff_for_gapp()``` [Renamed to ```check_is_gapp_for_gstaff()```]
            - ```get_group_type()```  [For applying url restriction]
     2) gnowsys_ndf/ndf/templates/ndf/gapps_iconbar.html
     3) gnowsys_ndf/ndf/templates/ndf/gapps_menubar.html

**3) Work regarding MIS template redesigning**

   - Files modified:
   
     1) gnowsys_ndf/ndf/templates/ndf/mis_base_create_edit.html
     2) gnowsys_ndf/ndf/templates/ndf/mis_base_list.html
     3) gnowsys_ndf/ndf/templates/ndf/mis_create_edit.html
     4) gnowsys_ndf/ndf/templates/ndf/mis_details.html
     5) gnowsys_ndf/ndf/templates/ndf/mis_list.html
     6) gnowsys_ndf/ndf/templatetags/ndf_tags.py - html_widget() updated
     7) gnowsys_ndf/ndf/templates/ndf/event_create_edit.html
     8) gnowsys_ndf/ndf/templates/ndf/person_create_edit.html

**4) File renamed:** from ```add_fields_to_existing_documents.py``` to ```sync_existing_documents.py```

**5) User-access policy updated**
   - Group-admin check added

   - File modified:
   
     1) gnowsys_ndf/ndf/templatetags/ndf_tags.py - user_access_policy() updated