Add Selenium Test for Making a Selection with Mousemove

[chenba]

Add a test for drawing a selection box for a shot.

[chenba]

With selenium-webdriver 4.0.0-alpha.1 and geckodriver 1.10.0 or 1.11.0 (and a 61.0a1 Nightly), perform a mouse selection with press().move().release() does not work. The selection is started but then never finishes.