Doc: Modularize QtGui documentation.

This change moves the snippets and images to the modularized
directories.

Change-Id: I5f86f598fbe7c47d632c613b85d94ced89ba2c29
Reviewed-by: Marius Storm-Olsen <marius.storm-olsen@nokia.com>

src/gui/accessible/qaccessible.cpp

@@ -460,7 +460,7 @@ static void qAccessibleCleanup()
     This is a typedef for a pointer to a function with the following
     signature:
 
-    \snippet doc/src/snippets/code/src_gui_accessible_qaccessible.cpp 1
+    \snippet code/src_gui_accessible_qaccessible.cpp 1
 
     The function receives a QString and a QObject pointer, where the
     QString is the key identifying the interface. The QObject is used