Merge pull request #60 from alice/master

Add reasons to focus properties, test for same.
Look at individual clientRects rather than boundingClientRect for overlapping element check; potentially return more than one overlapping element.
Update Properties.js to use overlappingElements rather than overlappingElement; correctly detect inherently focusable elements and add in hiddenReason
Merge pull request #61 from alice/overlapping

Look at individual clientRects rather than boundingClientRect...
Fix test failure in get focus properties test
Merge pull request #62 from alice/fix

Fix test failure in get focus properties test
Fix infite loop when getting descendant text content of a label containing an input
Merge pull request #63 from alice/labels

Fix infite loop when getting descendant text content of a label ...
Add test for Issue #69
Force focus before testing visibility on focusable elements.

[Finishes #65]
Move GUI only tests into their own test file
Merge pull request #68 from ckundo/dropdown-focus-test

Force focus on elements before checking if they are visible (e.g. skip-nav links)