Expose all grants

This exposes all the other grant types as examples.  They are:
* Implicit
* Resource Owner Password Credentials
* Client Credentials

**Testing**
Go to my wiki here for testing using the chrome plugin of Advanced Rest Client
https://github.com/FrankHassanabad/oauth2orize/wiki

**Notes**
I had to change the BearerStrategy implementation within examples/express2/auth.js to work with the Client Credentials grant since when using that grant type there is no notion of a userid/password. (Is there a better way such as multiple BearerStrategies?)

For Client Credentials I had to add an extra file of 
* examples/express2/client.js 

to show client information for demonstration purposes.