Phonon broken include for Linux

Includes regarding Phonon for Linux platform were broken for last Phonon libraries.

In file GAudioOutput.h, include lines for Phonon libraries where modified, line 44 to 45

From:

    #include <Phonon/MediaObject>
    #include <Phonon/AudioOutput>

to:

    #include <phonon/MediaObject>
    #include <phonon/AudioOutput>

Hope this helps, even when more errors are present