hub 2.2.0-rc1

• Add csh & tcsh shell support
• Fix script/build on Windows. For running this, GitHub for Windows command prompt is needed.
• Fix detecting base branch for pull-request
• Fix authenticating on GitHub Enterprise
• Skip looking into SSH config if current URL scheme is http or https
• Treat remote URL user name case insensitive when creating PR
• Fix index out of range issue when parsing global flags
• Remove editor file after pull-request is there’s no title
• exec the final git command run instead of running it as a subprocess: fixes subtle issues like git pagination getting messed up if parent process is aborted.
• Don’t trim empty CLI arguments
• Change authentication process to create a new token every time instead of reading previous one from GitHub API, which is a feature that's going away for security reasons.
• Avoid showing warning about invalid 2FA code on first prompt
• URI-encode most characters in branch names for compare command
• Allow creating "origin" remote in create even if another remote exists
• Auto-private URLs in remote add when matching your own repos