add session_save with new command_t struct to libjack.py
add session_save with new command_t struct to libjack.py

drobilla/jack1,ventosus/jack1,adiknoth/tschack,drobilla/jack1,ventosus/jack1,ventosus/jack1,adiknoth/tschack,drobilla/jack1,ventosus/jack1,drobilla/jack1