Add support for working offline

[Scott Wells]

I thought I already had this in the backlog, but evidently not. It would be nice to be able to tell IC that you want to work offline, at which point IC would optionally snapshot the current state of deployment and then stop performing any operations that require a server connection. When IC is told to go back online, it would optionally reconcile things and catch the server up to the current state.

This will be even more useful when I add local code inspections and intentions that ensure that code is valid even before it has been sent to the server for compilation/validation.

[Scott Wells]

Issue tracker grooming. It's hard to imagine a true offline mode for IC2 at this point given that the development model is so tied to an org. If there are specific issues when trying to work locally without attempting deployment/retrieval/etc., those should be logged separately.