Add Open Sans about fonts

[adrientetar]

https://www.google.com/fonts/specimen/Open+Sans
&
https://github.com/google/fonts/tree/master/apache/opensans

?

It is one of the most viewed fonts on GWF.

[davelab6]

@crispinbixler where do you expect it? :)

[rsheeter]

To clarify, it is not the intent for paths in this repo to mirror the paths on www.google.com/fonts. Here the fonts should be underlicense/family, hence apache/opensans.

[crispinbixler]

Ok, makes sense. I'm a beginner and sometimes the wording of things goes over my head even though as I re-read the README it makes perfect sense. I just jumped in too quickly and only looked in the ofl and ufl folders and didn't check apache! Thanks for the clue :) :)