Introduce UserAction which distributes actions by the username.

There are n UserActionActors (n = number of cores).
ConsistentHashingRouter determines which UserActionActor executes the
given action by the hash code of username.

Removed Authenticated object and made Session.logout use UserAction
instead of Authenticated.
Make every request timeout in 30 seconds.

Created TimeoutFilter to intercept all incoming requests and timeout if a
request is not completed in 30 seconds. The timeout duration is fixed to 30
seconds for now, but it needs to be configurable.
Add admin page header.

Currently, there is only Home tab.
Show the server information in admim home page.

The server information includes:
- Play mode
- PlayVersion current
- PlayVersion sbtVersion
- PlayVersion scalaVersion

More will be added later.
Change the background color of body to #fff.

Bootstrap sets background-color: #fff; on the body
Change admin header template to a React component, <Header>.

Also changed to use the style of Bootstrap Dashboard example:
http://getbootstrap.com/examples/dashboard/#
Add require.js.
Add require-jsx.

require-jsx is a plugin for JavaScript files containing JSX.
https://github.com/seiffert/require-jsx
Configure RequireJS to use JSX.

This is required to use React with RequireJS.
Extract Header as a RequireJS module.
Extract TablePanel as a RequireJS module.
Extract LoginForm as a RequireJS module.
Update README.md to describe how to run Beyond
Load React using RequireJS.
Load jQuery and Bootstrap using RequireJS.

Move public/javascripts/jquery-1.9.0.min.js to public/jquery-1.9.0.min.js
because we keep external JavaScript libraries under public directory.