fix: Implement BARTAPI.refreshCache so that it actually passes tests and fills out data in idb
fix: Implement BARTAPI.refreshCache so that it actually passes tests and fills out data in idb

This was made simpler by by putting the
common code for getting text out of a response into fetch(), rather than
every fetch_* function.

avitevet/udacity-transportation-app,avitevet/udacity-transportation-app