software/js-drone: call onStart with a timestamp

The function `onStart`, first function called when running the user script, has
now a timestamp provided to indicate when was the script started.

software/js-drone/buildout.hash.cfg

@@ -34,7 +34,7 @@ md5sum = 9418396fc75e820b9dd5e913855aafe2
 
 [main]
 _update_hash_filename_ = drone-scripts/main.js.jinja2
-md5sum = 4d13e382ba6462e19b67aa67207324dc
+md5sum = af7f13928f5b6ada0ea5c841325b86f2
 
 [pubsub]
 _update_hash_filename_ = drone-scripts/pubsub.js.jinja2
@@ -46,4 +46,4 @@ md5sum = c3858b5ec7373a0932fcda911a8177b5
 
 [worker]
 _update_hash_filename_ = drone-scripts/worker.js.jinja2
-md5sum = 4624b7a0a71c6abe6086b0c628074498
+md5sum = 4d6639424300a5f165730de6e267543a

software/js-drone/drone-scripts/main.js.jinja2

@@ -177,6 +177,7 @@ import { err, exit, open, out } from "std";
       operator_path: operator_script,
       map_path: map_json,
 {% endif -%}
+      timestamp: Date.now(),
       user_path: user_script
     });
   }

software/js-drone/drone-scripts/worker.js.jinja2

@@ -203,7 +203,7 @@ import { evalScript, fdopen, loadFile, open } from "std";
     return script_content;
   }
 
-  function loadUserScript(path) {
+  function loadUserScript(path, timestamp) {
     var script_content = getFileContent(path);
     try {
       evalScript(
@@ -221,7 +221,7 @@ import { evalScript, fdopen, loadFile, open } from "std";
 
     // Call the drone onStart function
     if (user_me.hasOwnProperty("onStart")) {
-      user_me.onStart();
+      user_me.onStart(timestamp);
     }
   }
 
@@ -261,7 +261,7 @@ import { evalScript, fdopen, loadFile, open } from "std";
       break;
 
     case "load":
-      loadUserScript(evt.data.user_path);
+      loadUserScript(evt.data.user_path, evt.data.timestamp);
       if (evt.data.hasOwnProperty("operator_path") && evt.data.hasOwnProperty("map_path")) {
         loadOperatorScript(evt.data.operator_path, evt.data.map_path);
       }