encoder: user can choose which encoder instance will be read

Signed-off-by: Michael Geszkiewicz <micges@wp.pl>
add comments for encoder access example

Signed-off-by: Michael Geszkiewicz <micges@wp.pl>
encoder: scale tsc timer to get 1000 ticks between reads regardless of current --delay argument

This will allow precise velocity estimation.

Signed-off-by: Michael Geszkiewicz <micges@wp.pl>
sserial: add support for 7i77 analog sserial remote, add also example program for it

Signed-off-by: Michael Geszkiewicz <micges@wp.pl>