Update comments to mention that each turnstile contains two queues and to describe turnstile_disown() and turnstile_empty().
Update comments to mention that each turnstile contains two queues and to
describe turnstile_disown() and turnstile_empty().

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