Updated README

Descriptions of individual one-off Javascripts.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>
Timing Update

Updated hide-future-courses.js to simply keep retrying until the variables and/or DOM elements required are available (as in [dev-faculty-journal](https://github.com/smtech/canvas/commit/38955ef47b33478d0549712689844734dc66001d))

Also, re-added discussion-permalinks.js back into global.js.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>
Flagged Future TODOs

I would like to update these Javascripts to be consistent with the new work in faculty-journal.js. We'll get there. Someday.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>