Better support for dynamic and important plugins

[daywalker90]

I identified a few issues related to the title:

• dynamic plugins are not added to the internal state, so things like listor remove don't work
• help text should make clear that enable and disable are for static plugins only and make a start and stop command for dynamic plugins
• • OR overload enable and disable for dynamic plugins to be their start and stop
• using remove should stop a dynamic plugin
• plugin authors need to be able to mark their plugin important in the manifest and coffee should support that

I can make pr's for these if you like, but i wanted to gather some feedback first.

[vincenzopalazzo]

There are really good points thanks, I think we should implement these too before our 0.1.0-rc1 because looks like basic functionalities