Remove Unmaintaned Frontends from Tools.

The unmaintained Rango frontend and the Hugopit "experiment" should be removed from the Hugo Tools/Frontends section of the documentation as they are unusable.

Rango can mess up with other dependencies installed in the Go Path as reported here: 
https://github.com/stayradiated/rango/issues/4

Hugopit's developer himself stated that this is an unmaintained experiment and he seemed a bit surprised that it is included in Hugo's documentation over here: https://github.com/sjardim/Hugopit/issues/3

docs/content/tools/_index.md

@@ -77,10 +77,8 @@ If you don't want to use [Wercker for automated deployments]({{< relref "tutoria
 
 Do you prefer an graphical user interface over a text editor? Then give these frontends a try:
 
-- [rango](https://github.com/stayradiated/rango) - A web frontend for Hugo. It's designed to make it easy to manage a small site, even for people with little computer experience.
 - [enwrite](https://github.com/zzamboni/enwrite) - Evernote-powered statically-generated blogs and websites. Now posting to your blog or updating your website is as easy as writing a new note in Evernote!
 - [caddy-hugo](https://github.com/hacdias/caddy-hugo) - This is an add-on for [Caddy](https://caddyserver.com/) which wants to deliver a good UI to edit the content of the website.
-- [Hugopit](https://github.com/sjardim/Hugopit) - A web-based editor for Hugo build on top of [Cockpit CMS](http://www.getcockpit.com/).
 - [Lipi](https://github.com/SohanChy/Lipi) - A native GUI frontend written in Java to manage your Hugo websites.
 
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