Announced Course Edit

MIS Announced Course Updates 

Files changes:
[1] /ndf/templates/ndf/announced_course_create_edit.html
     - Removed buttons "View" and "Get Colleges", now placed their same ajax calls on change of dropdown lists viz. Course_type_list and University_list.
     - Re-positioned html widgets
     - Disabled all template elements for Announced Course edit, allowing only the end_enroll date of Student enroll duration to be changed. 

[2] ndf/views/ajax_views.py
     -  Modified get_courses().  start_time and end_time of course duration are not required for fetching the courses.
[3] /ndf/views/course.py
    - Announced Course name created as "Course_code_College_code_duration_start_date_duration_end_date"
   - Edited course is saved by changing only one attribute field "end_enroll"

[4] /ndf/templates/ndf/new_create_batch.html
   - Constraint added:  A batch must hold minimum 20 members for creation

[5] /ndf/templates/ndf/student_create_edit.html
   - Removed code previously added by me for datepicker positioning.