buildFragment.xml: Enable Java 1.7 for the Haiku build
Haiku: skeleton for widget creation/disposal, event handling

* Set up the basic widget and display creation and disposal methods.
  A lot of actual implementation is still missing.
* Implement bare bones Shell creation and disposal.
* Implement the basics for the native event handling. We create a
  BApplication (HaikuApplication) on demand, a display message queue
  (HaikuDisplay), and windows (HaikuWindow) which redirect their
  message to the display message queue. Display.readAndDispatch() pops
  a message from the queue and lets the window handle it.

This makes HelloWorld1 (creating a shell and waiting for it to be
closed) work.