Video and audio only profile switching not working

[paulgration]

Prior to commit 3f5cb3a8b2fcffdd5c00df4701f0010e2977a98b when starting Galicaster with a video profile and switching to an audio only profile then switching back to a video profile the video preview doesn't get displayed again, Galicaster stays on the audio only preview state and it wasn't possible to get the video preview to display again so this wasn't functioning correctly..

Since 3f5cb3a8b2fcffdd5c00df4701f0010e2977a98b starting Galicaster with a video profile and switching to an audio only profile now raises an exception and the video preview freezes:

Traceback (most recent call last):
  File "Galicaster/galicaster/recorder/service.py", line 130, in drawing_areas_wrapper
    areas = self.__create_drawing_areas_func(info)
  File "Galicaster/galicaster/classui/recorderui.py", line 497, in create_drawing_areas
    source = sources[i]
IndexError: list index out of range

Subsequently switching to a video profile again restores the video preview