v1beta16 api support

[paulrossman]

• v1beta16 introduces a new quota structure that has the following changes:
  • All zone quotas have been removed and will no longer be enforced or reported.
  • Regional resources now have quota information and take the place of old zone quotas.
  • Certain global quotas have been removed or migrated to become regional quotas.
• Added support for GCE regions
  • knife google region list
• Added support for GCE projects
  • knife google project list
• Added service account scope support when creating new servers.
• Update UA string to knife-google-v1beta16
• Bumped knife-google version to 1.2.0

[adamedx]

Overall changes look good (I focused on the non-cosmetic commits). Only issues I have at this point are in the README:

1. What's the key purpose of the project list command? So I can know if I have enough resources to spin up instances?
2. I'm sort of confused about when to use zones vs. regions. I was able to spin up instances fine just specifying a zone. Maybe this is very obvious for GCE users and doesn't belong in this readme, but at least a little information would help me here in ensuring I get all the reasoning behind these changes.

[erjohnso]

@paulrossman - friendly ping. Perhaps a bit more clarity in the README around the points that Adam raised?

[paulrossman]

I'll make changes to the readme and update the PR today.