Online exchange of a nested simulation via loading *[ir].par files
[sim, out] = ld_nested_exchffile(sim, events, compresult, slot, fname, simnest_name)
NOTE: May delay realtime behaviour - use during a asynchronous nested simulation
compresult - signal
slot - signal
fname - the filename without ".[ir]par"-ending
simnest_name - the string which referes to the nested simulation (as given to "ld_simnest2")