Add documentation links

[darthdeus]

There are many useful documentation browsers

• http://conj.io/
• http://clojuredocs.org/
• http://crossclj.info/

and maybe even http://clojure-doc.org/, which is more of a tutorial style, but certainly helpful

[hura]

Other candidates:

http://jafingerhut.github.io/
http://cljs.info/cheatsheet/
https://github.com/martintrojer/go-tutorials-core-async
https://github.com/halgari/clojure-conj-2013-core.async-examples/blob/master/src/clojure_conj_talk/core.clj

https://aphyr.com/posts/319-clojure-from-the-ground-up-debugging

[mbuczko]

thanks, added. core.async resources pushed to the "projects" section.