initial popup intern functional test, fixes #117
Popup test cleanup (part 1), refs #117.

- remove "initial frames are hidden" test since iframes aren't created until needed
- remove unnecessary then() calls and wd variables
- indentation changes
- simplify some asserts, removing double negatives etc.
Popup test cleanup (part 2), refs #117.

Handle all the popup creation, opening, and closing from popup.html.
Popup.js triggers the show/hide of popups by clicking buttons.

Also, rolled aria attribute checks into an existing test.
buttons need to be visible to be clicked, refs #117
Rename enteredViewCallback() to attachedCallback().
Chrome doesn't handle querySelectorAll("").
remove bad commented iframe - sorry my fault