Support unselected and starred courses

[raxod502]

From @PythonNut on January 13, 2018 0:27

Presently, all courses are selected. The ability to select and star courses is important, so it will need to be reimplemented.

Plan

• Switch store's courseList field from a List to an OrderedMap and map from the courseIds to Maps with the selected and starred properties.
• Write four new actions w/ creators selectCourse, unselectCourse, starCourse, unstarCourse.
• Write the relevant reducers in src/reducers.js.
• Modify CourseListItem to send these actions.
• Update VisibleMainPanelSchedule to take these properties into account when computing the current schedule.

Copied from original issue: hyperschedule/hyperschedule#48