Missing VISCA_TERMINATOR on autofocus method

[fbbura]

The set of autofocus doesn't work. I checked on documentation:
https://www.axis.com/dam/public/70/3d/31/visca-interface-api-description-en-US-266656.pdf (page 2)

And I think that a terminator FF ( VISCA_TERMINATOR) is missing on VISCA_set_focus_auto method
https://github.com/mkoppanen/libVISCA2/blob/master/visca/libvisca.c#L520
I added the line
_VISCA_append_byte(&packet, VISCA_TERMINATOR);

It looks working now