Merge pull request #670 from cjakeman/menu-options03c

adds Help Icons to Audio options tab (again)

Author: cjakeman

Source/Documentation/Manual/images/options-audio.png

@@ -121,17 +121,24 @@ Audio Options
 
 .. image:: images/options-audio.png
 
-Except for very slow computers, it is suggested that you set the Sound detail level to 5.
+Sound Volume
+------------
+The *% sound volume* scroll button allows adjustment of the volume of OR sound. 
+
+Default is 40.
 
-The *% sound volume* scroll button allows adjustment of the volume of OR
-sound. Default is 40.
+Sound Detail Level
+------------------
+Except for very slow computers, it is suggested that you set the Sound detail level to 5.
 
-The *% external sound heard internally* scroll button allows to define the percentage
-of the original volume of external sounds heard in cab and passenger views. In fact
-in real world external sounds are attenuated when heard within a trainset.
+External Sound
+--------------
+The *% external sound heard internally* scroll button defines the percentage
+of the original volume of external sounds heard in cab and passenger views.
 This percentage may be overridden trainset by trainset as defined
 :ref:`here <sound-external>`.
 
+
 Video Options
 =============