This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.
This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
Again, mostly just copying what I see in other implementations. This
does seem to have done the trick so that I can now pause, fast forward,
rewind, etc., on my Samsung F series.
Brings in icons for devices to display. Based on what some
other open implementations have done, it's worth having a simple
stub implmentation of ConnectionManagerService. Advertise
X_MS_MediaReceiverRegistrar as well, which sounds like it
is necessary for certain MSFT devices (like the X-Box.)
