2 fixes as required by issue 185

[philipabbey]

Solution to a race condition with starting updates and amendment to error message presentation on Webhook ID creation failure.

[philipabbey]

I have already reviewed your race condition changes. So that should just leave the trivial WebhookManager.mc file changes I made.

[philipabbey]

This will not form a new release on its own, we'll just store it up for something bigger to come.