Consistent formatting and code style

In the spirit of keeping the formatting within the project consistent, I am proposing the following improvements:

* Convert spaces to tabs in the few instances where tabs were used to indent
* Convert docstrings delimited by `'''` to `"""` in the few instances where single-quotes were used
* Remove redundant `()` in conditional statements: `if (condition):` becomes `if condition:`

There are also a few bits of dead code which I suggest might be removed:

* The class `Counter` was buried within a method of `youtube_dl/extractor/crunchyroll.py` and never used.
*  `title` was inserted twice into the playlist in `youtube_dl/extractor/appletrailers.py`.
* Several local variables were never used and served only to confuse

Lastly, 

* `if condition == False:` is idiomatically written as `if not condition:`
* `+=` simplifies `Utils.timeconvert` a bit