• Clean up extraneous error messages in extensions commands.
• Adds breakpoint debugging for the Cloud Functions emulator using the --inspect-functions flag (#1360).
• Adds the ability for the Hosting emulator start offline through emulators:start (#1854).
• Changes ext:install to display helpful links instead of post-install instructions.
• Sets the GCLOUD_PROJECT environment variable for scripts ran through 'emulators:exec'.