Edit label if it exists on destination with source's label

[samfranz]

Currently right now if a label exists on the destination project it triggers the Validation Failed error. Maybe add an option in can pass in where it would edit the existing label at destination with the label's properties of source. So editing the label's description, color, ect with what's on soure.

[OpticFusion1]

Hey, if you could re-make this issue on my fork that would be nice. This project's dead, and having these issues on my fork will make things easier on me :)