Change updaters. try: Empty, create, download in sb-update + pep8

+ Change Windows and Source update to the same flow.
    Delete sb-update, create sb-update.
    Download, extract in sb-update, delete tar/zip
    Update.
+ Use git return code instead of text
+ Don't crash on wrong build versions, just don't update
+ Change branch check for source, git. Also set SICKBEARD_VERSION = branch
+ Change git variables