hello_audio: better support for multichannel
Merge pull request #55 from JamesH65/camera_dev

Component creation functions changed to return status
hello_audio: support different sample rates
Merge pull request #57 from JamesH65/camera_dev

Fixed up so RAW works for each capture in timelapse mode
Re-enabled ISO setting - tests show (in EXIF data of test jpegs) you can set between 100 and 800.
Added the option to save the raw data as RGB888. This requires a change to the firmware.
Fixed up preview mode to use a null sink rather than not connecting
components. Fixes the darkening frames in timelapse mode problem.
Fix for compile fault due to mising change in the RaspiPreview.h header file.
Userland Issue #80

Possible fix for the exposure values being ignored.
Was setting a specific ISO rather than automatic by default
which was upsetting the -ex settings.