title: GtkEntry text change signal
body: <p>How can I connect a signal callback for any kind of change in a GtkEntry's buffer, including character added, deleted, text pasted or cut? I've looked in the docs for GtkWidget, GtkEntry and GtkEntryBuffer without finding this.</p>
  
  <p>Note: if my question was badly worded, think of the HTML DOM's <code>change</code> event, <em>except</em> that it's fired greedily after every single keypress or event that causes a change, and not only checked on unfocus.</p>