Update unused files.
Changes
This MR updates various unused files to be compatible with Python 3 and Gstreamer 1.0.
All affected files have been unused for a long period of time, but the changes are simple enough that it was harmless to do.
However, if they become difficult to review, we can delete them instead.
This repeats all changes from !226 (closed) for these files.
Purpose
I intend to split !226 (closed)'s changes into a number of MRs, which won't be functional code versions themselves, but once complete will encompass the full set of changes to upgrade to py3.
This should provide useful code diffs for reviewers.