Add Cheatsheet

[oubiwann]

Best cheatsheet I've seen for a language so far:
http://jafingerhut.github.io/
Do one like that for LFE.

Part of epic #75

[oubiwann]

Here's an Erlang one:
http://www.cheat-sheets.org/saved-copy/Erlang.CheatSheet%281.0%29.pdf

[oubiwann]

Hrm, there's content for this somewhere ... I think maybe in a repo? Maybe in open document format? Need to find it.

[yurrriq]

It would be awesome to emulate the Clojure Grimoire!