Move emitter.js to helpers/
Remove some dead files
Clean up deepFreeze by reindenting and es6ifying it.
Import emitter into loadData
Create prepareAndFreezeCourse
to clean up and add properties.
Compact some code in convertTimeStringsToOfferings
Update primeCourseCache
Reorganize a bit of studentSummary
"Account" for seminars in Chemistry
Remove CourseList; merge with Semester
Remove courses from their semesters when dropped
if dropped over a valid target (the `if didDrop` bit)
Rerender the app onchange the React-Preferred way
Add a course to a schedule when dropped on a schedule
Merge branch 'change-events' of https://github.com/hawkrives/gobbldygook into change-events

* 'change-events' of https://github.com/hawkrives/gobbldygook:
  Tweaked some requirement handling (and extraced some functions) from commonEducationRequirements
  Added a partial test for common education utilities
Call concat, not merge, to join two arrays of objects.
The test requires crsids to deduplicate between courses