Remove-MyCourses: MyCourses tab has been removed.

The MyCourses functions have been left, they may be valuable in the future.
Remove-MyCourses: Remove my_courses.js

I decided to remove my_courses.js. If we want to retrieve the functions again, then we can look at the project history.
Remove-MyCourses: Update planner.html.

Removed my_courses.js from planner.html.
Merge pull request #175 from Ian-Stewart-Binks/remove-mycourses

Remove mycourses