Set core, non-core exercises and unlocking ones (#330)
Set core, non-core exercises and unlocking ones (#330)

- There are 18 core exercises
- There are 3 exercises as non-core and without a locking exercise
tejasbubane/xecmascript,MattH-be/ecmascript,MattH-be/ecmascript,tejasbubane/xecmascript,exercism/xecmascript,exercism/xecmascript