Added formatting changes for to_string() method of graph objects.

before:

            text=[u'4179 Toutatis<br>Radius: 2188 meters <br> Velocity: 11....],

after:

            text=[u'4179 Toutatis<br>Radius: 2188 meters <br> Velocity: 1...'],

additionally:

* the end of line (eol) is considered in max len
* the conditional comma is considered in max len
* lines >= to max line length are guaranteed to equal max line length!
* to do the above, spaces, ' ', are filled as necessary.
At least close ']' for lists of lists. Sorry, lists of lists of lists.

Also, you have to ensure that the sublist is longer than "[...]".
Where "..." == end.

Otherwise, you might end up with: ", ...]". Where we're closing
something that we no longer open!
'...' -> '..' for to_string() overflow.

Higher chance that we see the end returned.
Merge pull request #101 from plotly/to-string-quote

To string quote