Write up front-end testing script

[davidheyman]

This is something you've done a lot of @buccalon so I think we should formalize it. It just needs to be a list of steps to go through to test all the features in the map so we can detect any issues (i.e., the annotation labels not displaying) that can't be detected using the automated tests.

Try using a format like:

1. Add a line annotation. Confirm the annotation has a line and label.

It doesn't need to cover everything, just the big things in the editor that are tough to get with automated tests and more likely to break.