Introduce PromptDialog and ConfirmDialog to solve #136
Convert remaining instances of prompt() to PromptDialog
Closure typo in refactor PromptDialog usage
More silly mistakes, PromptDialog-related.
Attempt to use ConfirmDialog for unsaved files
Use ConfirmDialog for unknown file types in source editor
Use ConfirmDialog for unsaved files on quit
Use ConfirmDialog for 'not yet part of project' prompts.
Use ConfirmDialog for close/close other/close all in editor panes.
Merge pull request #137 from fasterthanlime/unstable

Replace confirm, prompt with ConfirmDialog & PromptDialog