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.
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/conversion/ConvertString2Boolean.java
/* (non-Javadoc)
	 * @see org.eclipse.jface.binding.converter.IConverter#convert(java.lang.Object)
	 */
	public Object convert(Object source) {
		String sourceString = (String) source;
		if ("".equals(sourceString.trim())) { 
			return null;
		} else {
			return super.convert(source);
        }
	}
	public Object getToType() {
		return Boolean.class;
	}
}