Plugin registration is broken

[GordonGuenther]

I would like to write my own plugins for nocca, but the registration of external plugins through the configuration of nocca is not working, like described in docs/plugins.md, anymore (since october 2015).
On using my own plugin within an endpoint, i get the errror: "ERROR Cannot use plugin with id myKeygen as it is not loaded (ErrorHandler)"

This change was introduced in commit f9d5dd3

Is this a feature or a bug to only load files within your own plugin folder?