Reopen browser window when loading url

If the browser window has closed and the browser event is called with the
url attribute, this change causes VDD to reopen the window and then load the
URL.

This functionality is not currently used by the test suite, but it is very
handy for VDD regression tests.

Testing done:

Many iterations of the new sugarwait test, which closes and opens the window
several times.
Create SugarWait regression suite

Since SugarWait is such a fundamental component of testing Sugar with VDD
and it has proven in the past to have complicated interactions with VDD,
Sugar, and Selenium, it just makes sense for it to have its own regression
test.

The test added in this change hits all the corner cases of SugarWait that
have proven troublesome and also the normal cases as well.

This test is not being made part of the regular VDD regression suite due to
its slightly more complicated setup than the rest of the suite (path to
the plugin file must be specified for this test only), and also because
VDD changes rarely impact SugarWait functionality.

Testing done:

Many iterations of this test against SugarWait with output compared to
what it should be.