Give the option to kill all browsers and webdriver session while using DefaultSessionFactory methods

[shriverg1]

When running jobs on external machines users may want to ensure they have a clean environment to run their UI test from. In order to do this they will need to kill all other webdriver and browser related sessions before they start their test execution. Currently the DefaultSessionFactory has a method that kills only task related to the browser specified. This may cause issues if rogue webdriver sessions are open for other browsers.

[mmlinford]

So you're saying that if, for example, somebody's IE test fails and doesn't clean it up, it will not get cleaned up if the next person runs Chrome?

[hyaruixi]

Do we need this method? I remember EWD will kill session first before start a new one