Got pipe to work between movie subprocess and main code. We use it to
display progress from the scripts. Write "gstreamer raw" files, that
can be worked with easily from gstreamer.
Rename MPCameraMode to a more generic MPMode and move it along
with related functions to a new object in preparation for using
it in the device object.
clang-format always manages to mix spaces into tab-based indentation.
Since we already require an exact tab-width of 8 it makes more sense to
use spaces.
