Project relative dictionaries

[CareyJWilliams]

At the moment a single dictionary needs to be explicitly imported to CSIDE. This can make switching between projects that require different dictionaries quite painful.

One possible solution would be to have a concept of automatically detecting and loading 'dictionary.json' files in any opened projects (should one exist), and switch the language service to use whichever one automatically based on the active project.

I think the behaviour sounds quite promising, but performance could be an issue for larger dictionaries.

[CareyJWilliams]

@Fiogan suggested that it may be beneficial to forgo the UI altogether and just allow editing files (which should be text rather than JSON?) in the editors.