`clasp push --watch`, Autogenerated docs, improved exiting, Windows test support

This minor version improves the code and adds filesystem watching via clasp push --watch.

Internal

• Generated documentation. #200 #205
• Commands are separated into functions.
• Improved Auth scoping
• Using logError everywhere instead of console.log
• Windows test support #232
• Load credentials async #202

External

• clasp push --watch
• clasp -v (Updates with package.json) #229
• Standardized exit code. #218

Thanks for the contributions @campionfellin @wilt00 @rafasc @kant! 🎉

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