Test for configured client
Test that provider works with configured clients
Use Crockford style for Provider class
Check for configured client keys before checking DB
Pass config options to child as JSON-encoded values
Use a configured client ID as an OAuth client ID

In some situations (for example, a development group) you want to be able to set up and tear down new pump.io
servers with a consistent client ID.

This commit lets you set a clients array in the config.json file, for which each item is a client.
Add the clients setting to the README