Added list of plugins to config.
Restructured cli a little.
Added ext folder for plugins.
Removed ext folder.
Added cli plugin loading.

And removed server, as that became a test plugin.
Reduced some duplication.
Rewrote how the cli works to inject dependencies.

Also exposes the parts for the plugins - trust your plugins.
Removed markdown rendering.

The functionality can be implemented in a plugin.
Added Kasper to credits.
Merge branch 'master' into plugins

* master:
  Replaced GroupKey namedtuple with a class.
  Add build and dist folders to .gitignore
  Update requirements in setup.py to include jinja2
Rephrased comment.