Integration with SauceConnect

1. allow to run SauceLabs tests on Travis
2. solved problem where BrowserConfiguration's from ALL tests in test case file were disconnected from EventDispatcher once first test finished execution
3. the IAPIClient::updateStatus now returns operation result
4. a way to report test status back to BrowserStack (not tested yet)
5. support for running tests on Travis
6. don't attempt to stop not started sessions from strategies