dvbtee: add command line arguments & examples to README

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
dvbtee: add example 'To start a server using adapter 0'

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
README: add quick run-down of server commands

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>