Naming-conventions for configuration names.

[alexbrasetvik]

Some plugins are configured with "foo_name", while others call them just "bar". Same goes with "_path"-suffixes (pre-dating the !path-concept), "destination" vs "output", etc.

We should clean this up, before we get enough users to warrant dealing with a deprecation phase.

[nkvoll]

I think we should go with "foo" -- less typing and slightly easier on the eyes.

Regarding output_path, however, I'm conflicted -- I guess we rename this to 'output'?