This includes the following fixes:
1. fix error in `WindowMock.setWidthTo`
It was returning height, not width.
2. Fix for `WindowMock.reset`
Changes to the scroll position need to go
through the `scrollTo` method.
It also includes the following changes
1. Improve mocking of window scrollTop
Increases the number of DOM API methods mocked
to return the intended scrollTop value.
2. Change WindowMock.scrollBy to
WindowMock.scrollTo
Because you're not scrolling by an amount,
you're scrolling to a position.
3. Give WindowMock getters for position/dimension
It's useful to be able to get the
position/dimension of the window in tests when
you're resizing and scrolling it as part of the
test.
4. Assign WindowMock spies on instantiation
Assigning them whenever a dimension is set doesn't
make sense. You're just setting a value, not
changing how that value is accessed.
