NewTek NDI PTZ1 compatibility: don't use message counter

[vwout]

The sequence number in Visca messages in incorrectly handled by the NewTek NDI PTZ1. This camera is only capable of handling messages with seq_nr 1, 2 or 3 and it always responds with seq_nr=1. The work around is to not use sequence numbers:

modify libvisca.lua at line 941 and change:
message.seq_nr = self.last_seq_nr
to
message.seq_nr = 0

The original issue is reported on the OBS forum:

I tried the PTZOptics Mode but with that i had no camera movement at all. I added two logs from the OBS scriptlog. The first one shows 4 scene changes with 3 successfull cam preset recalls and the last one failing. The second log shows some unfinished messages that i get when i reload my script.

The workaround to not use sequence number is also confirmed there.