Implement command for creating a workspace
Implement prompt method for console
Create Before Sync method on watcher

So that account and app watchers can have different behaviors.
Implement workspace retrieval in GalleryClient
Allow file system to compute local file states
Implement conflicts identification in account watcher
Enable user to decide what to do with file differences

Fixes #17.
Creates conflict resolution with remote files
Take out of ChangeQueue the responsibility of getting change content
Resolve conflicts with local data