automate Monu.app releases

[max-mapper]

here's the algorithm:

• download atom-shell zip
• extract
• rename Atom.app to Monu.app
• copy entire contents of monu source folder into Monu.app/Contents/Resources/app
• rename CFBundleDisplayName, CFBundleIdentifier and CFBundleName fields in following plist files if they have these keys
• Atom.app/Contents/Info.plist
• Atom.app/Contents/Frameworks/Atom Helper.app/Contents/Info.plist
• test that the app works by double clicking it
• zip up Monu.app
• upload to github releases