Doc: Adding link to modules new in Qt 5.1.

-Qt X11 Extras
-Qt Serial Port
-Qt Sensors

Change-Id: Iae0cb013a593b8680b25ed214a4c373d86f376f7
Reviewed-by: Venugopal Shivashankar <venugopal.shivashankar@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

doc/src/modules.qdoc

@@ -179,11 +179,26 @@
         \li All
         \li
         \li Additional components for applications that use Qt Script.
+    \row
+        \li \l{Qt Sensors}
+        \li All
+        \li \l{Android}, \l{BlackBerry}, \l{iOS}, and Mer.
+        \li Provides access to sensor hardware and motion gesture recognition.
+    \row
+        \li \l{Qt Serial Port}
+        \li All
+        \li \l{Support for Windows}{Windows}, \l{Support for Linux/X11}{Linux}, and \l{Support for Mac OS X}{Mac OS X}.
+        \li Provides access to hardware and virtual serial ports.
     \row
         \li \l{Qt SVG}
         \li All
         \li
         \li Classes for displaying the contents of SVG files.
+    \row
+        \li \l{Qt X11 Extras}
+        \li All
+        \li \l{Support for Linux/X11}{Linux/X11}
+        \li Provides specific APIs for X11.
     \row
         \li \l{Qt XML}
         \li