Better multi-tab handling

Web driver is not easy to handle multi-tab. Basically it treats all browser tabs are equal. So it's hard to know which one is the front tab.
So many times my Stash_Helper is performing actions on a hidden tab, which is really bad.
Well, I finally have an idea to get the front tab. The implement is not pretty, but it works.
So thank you EoinBurke93 for the suggestion ! I like the Stash_Helper much better now. It finally works as it is supposed to be.