Add first draft of @def-lkb's post (for 20 Aug?)

For #6

This guest post covers both ocp-indent and merlin.

It could go up either Wed or Thu.
@def-lkb, I hope you don't mind if we post it on the Platform blog.
A the time of this writing, an interface to these tools is only available for *Emacs* and *Vim* although using them from other editors is definitely possible and some efforts exist for ...