We're currently working on a brand new Magento 2 theme based on the Snowdog Blank Sass parent. After a lot of research we've figured out a ton of cool features and insights on how to build a solid and extendable theme package. The thing we are not so sure about is how to make use of external frameworks and libraries like for example Bootstrap3 or Font Awesome.
We came across several cool ideas based on Bower, which can load packages from all over the place and include them inside the theme. The thing is, where do we put them and how is it all gonna work with Sass compiling. We pointed the Bower directory param to the //lib folder and put a git ignore in the root of the theme. Based on this idea, we can for example @import those into our _styles.scss file and make use of all the given mixins and variables.
In the end, I'm not totally sure if this is the way Magento wants it. I mean, the jQuery library is put inside the /lib/web folder which could act as a vendor folder for Bower. So in the same time I've explained it inside this topic, we've also tried it in practice and put Bootstrap-sass into the lib/web folder. Unfortunately this wont work because the static deployment will get stuck within the process mainly because it just doesn't know how to handle .scss files?
I hope some of you can help us find the right way / position of where to put all those libraries and framework. Bower can help allot if we get the right way.