Prevent committing when there are no changes

[jikkujose]

Problem:

• Commit a change
• Immediately issue another commit (possible because the sketch file will be shown as not added to the repo)
• A new commit will appear without any file change in it

[stephenedmondson]

+1 Seeing the same thing.

[krystof-k]

Yes, that's probably happening. Should be possible to solve, I'll try to look into this.