Remove jQuery; conditionally compile plugin system

[tomkwok]

• Replace jQuery with Zepto.js http://zeptojs.com/, which is much more lightweight. Zepto doesn't support IE 9 or below, but anyway we don't have to, as I, you and most, if not all, potential users of Journey don't use IE...

32K zepto.min.js
12K zepto.min.js.gz

84K jquery-2.1.4.min.js
32K jquery-2.1.4.min.js.gz

Note: I've added this line: window.jQuery=Zepto; so that we don't have to modify existing minified files from javascript libraries, namely autosize.js, bootstrap and bootstrap-fileinput.

• jQuery auto injection in {{ghost_foot}} is planned to be removed from Ghost. See 5 ways to fix the great jQuery debacle (no. 4 may surprise you) TryGhost/Ghost#5298. Let's do that in Journey.

---

@kabukky What new features are WIP?

---

[kabukky]

Great work, thanks! 👍
I haven't been following the developments around jQuery auto injection in Ghost, so this is a (welcome) surprise. I hated that behavior.
I guess we have to put that into the next release announcement as well, so that users won't be confused if their themes break.

I'm about to fork https://github.com/gorilla/feeds to customize it to our wishes.
Once that's done I guess it's time for another release.