Error Handling

[haydn]

There should be error message for each action like this:

Merge error. You've probably got merge conflicts. Resolve the conflicts and run this command again:
change stage example

Exit codes should also be returned.

Error types:

• merge error
• fetch error
• checkout error
• push error
• delete error?

[haydn]

This should include error messages like this:

Fix the merge conflict and then run this: change stage example --return-branch change/example