adds gating stuff, writes all thresholds simultaneously, updates readme with example

db/daq.proto

@@ -124,7 +124,7 @@ startWithTimePreset {
 }
 
 setMinRate{
- out "DL %(\$1THRESHOLD-MONITOR_RBV)d %.3f";
+ out "DL \$2 %.3f";
  in;
  @mismatch{in "%(\$1MsgTxt)s";}
 }