Clipboard resolver

[havardh]

Make it possible to resolve/load content from the local clipboard. This will make it possible to make an online example and execute it locally without copying down the file.

Proposed design

To activate this functionality we would need to add a command line flag to the workflow command. Something like workflow --clipboard.

Obstacle

The current api of a resolver returns an absolute path which can be loaded. The clipboard functionality fall a bit in the middle of a loader and a resolver at the moment. We could consider expanding the resolver api to return an object with either a path or a content variable. And making the loader load from a string when the resolver return the content. The further complication would be the planned addition of multiple loaders. The problem is to decide which loader to use when the content is resolved from the clipboard.