Only stash changes if it's actually needed

[Chronial]

Most of the time when I run git up, there isn't actually anything to do or only fast-forwards that don't need any checkouts. git up could run a lot faster in these cases if it would avoid stashing my changes.

[msiemens]

That's a good idea. This would first depend on #81, right?

[Chronial]

indeed.

[msiemens]

Closed by #86 🙂