Two proposals in this PR: Python 3.4 support and Exposing current tab instance in template

Both commits are independent (even though consecutive and you can merge both if your like them), both cover testing and documentation independently. Hope you accept them :)

In any case, thanks for your nice project.
Haha, funny that you commented just now. That fact also occured to me 5 minutes ago. So the `current_tab` variable is entirely unnecessary.

I'll add documentation for the `view` variable instead.