Clarify the description of the callout_active() macro: It is cleared by callout_stop, callout_drain, and callout_deactivate, but is not automatically cleared when a callout returns.
Clarify the description of the callout_active() macro: It is cleared by
callout_stop, callout_drain, and callout_deactivate, but is not
automatically cleared when a callout returns.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase