v0.8.4

• show error if there's no commit author set
• show error if we can't launch editor
• cover more values for the color.ui setting (thanks to @vmx)
• fixed potential unicode encoding errors (thanks to @knowsuchagency)
• changed reqs declaration to use current version of pygit2 (thanks to @scottsideleau)
• other misc fixes: updated link to google python style guide on readme (thanks to @rdpate), include full copy of GPLv2