Code review comment for lp:~mjthompson/openlp/media_plugin

Sorry but this will break the other plugins.

adding self.ServiceItemIconName will be required by all plugins now

Also is incorrect.
        - service_item.addIcon(u':/media/media_image.png')
92 + service_item.addIcon(self.ServiceItemIconName)

should be
          service_item.addIcon(u':/media/media_' + 'self.ShortPluginName + u'image.png')
This does not work for bibles as the media_image for bibles is _verses instead of _bibles.

Use of assert causes problems and rejections on a number of boxes can we have throws error instead.