clarifying comment in sim_init for default timeout
clarifying comment in sim_init for default timeout

rwcarlsen/cyclus,mbmcgarry/cyclus,hodger/cyclus,hodger/cyclus,hodger/cyclus,rwcarlsen/cyclus,gidden/cyclus,Baaaaam/cyclus,gidden/cyclus,Baaaaam/cyclus,hodger/cyclus,rwcarlsen/cyclus,rwcarlsen/cyclus,mbmcgarry/cyclus,hodger/cyclus,mbmcgarry/cyclus,Baaaaam/cyclus,gidden/cyclus,gidden/cyclus,mbmcgarry/cyclus