Updating URIs
* The Coinbase API does not accept URIs on the www subdomain.
Updated OAuth2 example
* Fixed critical bugs (URIs were non-functional)
* Reduced default scope to 'transactions balance' instead of 'all'
* Added helpful messages for common problems that new developers will run into (secrets file not existing, no notification when web server was starting)
* Added an off-by-default way to disable certificate validation