Example: Chat -- Welcome message is always on top. Click now focuses input.

Added two features to Socket.IO Chat:
 - **Click to focus**: Clicking anywhere now focuses the current text input.
 - **Welcome messages always on top**: (Even when messages are being loaded while still on the login screen.)
   - This was a bug where we connect and started loading messages/logs while on the login page. Once we actually logged in, the welcome message would appear below all of these messages. Now the welcome message is always on top.
    - Another way to do this would be to not load _any_ messages until the user logged in.
    - **Implementation**: Changed `addMessage` function to accept an `options` argument that have the boolean flags `fade` and `prepend`.