Add serial parameter to HMVP.Monsoon.setup_usb
Add serial parameter to HMVP.Monsoon.setup_usb

Add parameter serial to HMVP.Monsoon.setup_usb to allow
selection of connected device by serial number.

Edit: Originally I created this patch against
0.1.64 where the serial number could not yet be specified.
I would still like to suggest this solution, because I find it
somewhat more elegant.

msoon/PyMonsoon,msoon/PyMonsoon,msoon/PyMonsoon