Issue #11 (Browser Session index not reset)

Fixed a bug where the session browser index was not being reset on Close all browsers
Added some unit tests around that fix.

Feel free to take this code, or rewrite it. This is the solution I wrote to work around the problem. 

Thanks for your very quick responses, we really appreciate the awesome work you do. This is why I tell you to feel free to rewrite my code, your work is far beyond mine.