add scaffolding for pocsag decoding

htdocs/index.html

@@ -187,6 +187,7 @@
                         <option value="jt9" data-feature="wsjt-x">JT9</option>
                         <option value="ft4" data-feature="wsjt-x">FT4</option>
                         <option value="packet" data-feature="packet">Packet</option>
+                        <option value="pocsag" data-feature="pocsag">Pocsag</option>
                     </select>
                 </div>
                 <div class="openwebrx-panel-line">

htdocs/openwebrx.js

@@ -2160,6 +2160,7 @@ function demodulator_digital_replace(subtype) {
             demodulators[0].set();
             break;
         case "packet":
+        case "pocsag":
             secondary_demod_start(subtype);
             demodulator_analog_replace('nfm', true);
             break;