switch around
It's not unknown just > 100 commits
Add gh_api compare

Use gh_api compare to find behind_by in source updater

Change git updater. Switch to real git commands, using lad1337/XDM as example.

+ Change source updater. Get commits behind directly using github api compare

Add downloaded update file corruption check
Add extra log lines
Add stdin to subprocess.Popen to prevent WindowsError: [Error 6] The handle is invalid on pythonw