Initial commit for Vaadin 7.2
Added components

  Added a Label
  Added a TextField
  Added a PasswordField
Changed the vertical layout to a horizontal layout
Changed the horizontal layout to a form layout
Added a margin to the layout
Set size on the login field
Set height on the dynamically added label
Added a page title via the API
Change the way to add the page title from API to annotation
Extracted the servlet configuration into a dedicated class
Refactored the listener to a top-level abstraction
Extracted UI component into its own class
Changed from a fixed FormLayout to a CustomComponent
Added a new MainScreen component
Implemented a basic switch screen listener
Added a simple notification after authentication
Implemented a simple authentication logic and the relevant error notification
Store the user name at login and display it on the main screen
Updated the main screen with needed components
Implemented the send message feature