Add Router context support

[typerandom]

Adds support for emitting account and authenticated contexts from the Router.

Note

I have deprecated the UserComponent and UserField, since those are no longer needed when we have the account context.

How to verify

1. Checkout this branch.
2. Build it ($ npm run build).
3. Link it ($ npm link).
4. Checkout the the React example app.
5. Link to our React SDK feature branch ($ npm link react-stormpath).
6. Open up src/pages/ProfilePage.js.
7. Edit the page to look import the account context (as shown in this gist).
8. Start the app ($ npm start).
9. Navigate to /login.
10. Verify that you were navigated to /profile (the page we modified) and that the field values are shown.
11. Add a console.log(this.context.account); in the render() method of the ProfilePage and verify that the account is written to console.
12. Login and logout, and verify that the account is undefined when logged out, and an account object when logged in.
13. Do steps 11-12 but for the authenticated context.

Documentation

See: https://github.com/stormpath/stormpath-sdk-react/blob/feature-context-support/docs/api.md#contexts

Fixes #1.

[timothyej]

Don't you mean "If you want to know if the user is authenticated or not, include the authenticated context."?

[typerandom]

That sounds better! Thanks!

[timothyej]

At step 13, when logged out, printing this.context.authenticated in the header will be printed twice. First as false and then as true.

[typerandom]

@timothyej All of these things have now been fixed except for the ES2015 semicolon.

[timothyej]

Good work! 👍 ⭐

[typerandom]

\o/