Expose createIdentity, generateToken & sendAuthorizationRequest

[ericlu88]

This PR modifies the binding layer code to be almost 1-to-1 mapping to the C++ SDK, specifically around the authorization requests. The authentication/authorization is now following the same 3 steps as documented in the developer guide:

• session.generateToken(): Generate token based on the session options. Async. Generate TokenGenerationSuccess or TokenGenerationFailure events.
• session.createIdentity(): Create opaque identity object. Sync. Return a javascript identity object.
• session.sendAuthorizationRequest(): Send authorization request based on token & identity. Async. Generate AuthorizationSuccess or AuthorizationFailure events.

This change also removes the default identity that used to stored inside the binding layer, and update the AuthorizationApplication.js example.

This closes #43, #44, #45

[apaprocki]

Can you do a quick check on the formatting to see if anything exceeds 80 cols? I'd like to keep this < 80 cols according to the BDE standard for easier reading in a standard shell.

[ericlu88]

Re-formated lines > 80 columns.

[apaprocki]

lgtm