Quit after undo

[Zarathustra2]

Minor bug

Since #25 users cannot leave the editor with :q if they have unsaved changes.

If I edit a file but undo it till the state I opened the file, I am still forced to quit with :q! even though there are no changes.

I think this could be solved if for the file maybe a hash would be saved of the last saved state.
But I am not sure if this is the best way to solve this minor problem.

[itchyny]

Ah, ok. I'll fix this in a few days.

[itchyny]

Sorry for keeping this open for months, this is now fixed.