title: Disable AND grey out an SWT composite
body: <p>I have a <code>Composite</code> that I want to be able to enable/disable programatically. The <code>Control.setEnabled(boolean enabled)</code> method works fine, but it does not give any visual information that the widget(s) are disabled.</p>
  
  <p>What I would like to do is to have the disabled state mean the widgets are greyed out. Right now they just enter a weird state where the user is unable to click or perform any action on them.</p>