Create compact/struct.py for python2/3 compatibility
Create compact/struct.py for python2/3 compatibility

support for unicode literals in the struct package was added in 2.7.8.
This makes sure older python versions recieve normal str() objects. It
behaves like a drop in replacement for the builtin struct module, just
replace

import struct

with

from pyvisa.compat import struct

hgrecco/pyvisa,pyvisa/pyvisa,MatthieuDartiailh/pyvisa