View source for Missing Icon of the PulseAudio Applet

'''Problem:'''
* The PulseAudio Applet shows a generic blank page icon.

'''Reason:'''
* The used icon theme does not provide the ''stock_line_in.svg'' icon.

'''Solution:'''
* Copy the icon to use in the followind directory: ''/usr/share/icons/{MyUsedTheme}/scalable/stock/media/''.
* The name of the icon must be ''stock_line_in.svg''.
* Add the following lines to the end of the file ''/usr/share/icons/{MyUsedTheme}/index.theme'':
 [scalable/stock/media]
 MinSize=1
 Size=48
 MaxSize=256
 Context=Stock
 Type=Scalable
* For more details, see [https://bugs.launchpad.net/ubuntu/+source/padevchooser/+bug/431015].