Create test that fully expands all dynatrees and displays all screens

[jirkadanek]

Inspired by issue DISPATCH-751 Clicking entities/connector in stand-alone console prints "Error: [ngModel:numfmt] Expected 1 to be a number"

Check that no errors were printed. This will be bit tricky, because new W3C standardized WebDriver does not have API to simply read browser log. Useful even without this feature, when test is watched by person.

[jirkadanek]

This can be also used to generate up-to-date screenshot gallery for docs. Or for visual diffing.