Bug 167450 [DataBinding] Get rid of bind support factory magic
I finally realized that we don't need that other magic factory. I'll move fillBindSpecDefaults() and the methods it calls (createConverter, createValidator etc) to a new class DefaultBindSpec. Clients who want default validators and converters created for them just create a DefaultBindSpec as opposed to a (rather empty) BindSpec. I will also move the early type checking into DefaultBindSpec to make it optional as well.
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/databinding/DatabindingContextTest.java
protected void setUp() throws Exception {
		super.setUp();
		Realm.setDefault(SWTObservables.getRealm(Display.getDefault()));
	}
	public void testDisposeBindings() throws Exception {
		DataBindingContext dbc = new DataBindingContext();
		Binding binding = new BindingStub(dbc);
		dbc.addBinding(binding);
		assertFalse(binding.isDisposed());
		dbc.dispose();
		assertTrue("binding should be diposed when dbc is disposed", binding
				.isDisposed());
	}
	public void testDisposeChildContexts() throws Exception {
		DataBindingContext dbc = new DataBindingContext();
		DataBindingContext child = new DataBindingContext(dbc, Realm
				.getDefault(), new BindSupportFactory[0]);
		Binding binding = new BindingStub(child);
		child.addBinding(binding);
		assertFalse(binding.isDisposed());
		dbc.dispose();
		assertTrue(
				"binding should be disposed when a parent context is disposed",
				binding.isDisposed());
	}
	public void testBindValue() throws Exception {
		DataBindingContext dbc = new DataBindingContext();