- now call load, start, free PLC from the python Thread

- add a wx timer (500ms) that pull the plc state to refresh Beremiz icons
(fix problem when command PLC with the TaskBar icon)

[TOPOLOGY]
NetName=None
Nodes=0x01
Node3Present=0x01
Node3Name=slave
Node3DCFName=slave.eds
EDSBaseName=eds