Add ocamlformat for emacs setup

[sangwoo-joh]

Hi.

I've added some implementations to integrate ocamlformat into Emacs setup (#40)
I only added this to Emacs setup just because my primary editor is Emacs.
It binds C-c C-f to call ocamlformat for the current buffer.

Please review this pull request.
Thank you.

[rjbou]

Thanks for the PR! as a vim user, i'll ping @AltGr for this one

[jberdine]

I wonder whether this should consider also setting (add-hook 'before-save-hook 'ocamlformat-before-save)?

I'm also not sure if there is a standard key binding that most use. For one data point, I shadow the keys tuareg-indent-phrase to invoke ocamlformat, so M-q and C-c C-q.

It is also not completely obvious in which mode map to put these bindings. Is it ok to hijack tuareg-mode-map with not-so-related bindings?

[sangwoo-joh]

@jberdine Thanks for your comment.
Regarding (add-hook 'before-save-hook 'ocamlformat-before-save), I think it should also consider the setting.
Regarding key bindings, I'm also not sure if there is a dominant key biding standard. I'm wondering if there is a way to get a key binding from user input.
Regarding hijacking, I just added it to tuareg-mode-map because it was the way I've used for a long time. If there is a better way to do this, please let me know.
Thank you.

[punchagan]

@rjbou @AltGr This PR seems reasonable to me. What does it need to get merged? Is it waiting on adding support to ocamlformat to the other editors as well?

I have some time in the next couple of days, if there's any thing I can do to help. :)

[AltGr]

Oh I am sorry this completely passed under my radar. Thanks for the contribution, and this seems good to me!