code: public int addScriptsFromDir (File dir) {
  		logger.debug("Adding scripts from dir: " + dir.getAbsolutePath());
  		trackedDirs.add(dir);
  		int addedScripts = 0;
  		for (ScriptType type : this.getScriptTypes()) {
  			addedScripts += addScriptsFromDir(dir, type, null);
  		}
  		return addedScripts;
  	}
docs: Adds the scripts from the given directory and starts tracking it.
  <p>
  The directory will be tracked to add or remove its scripts when a new script engine/type is added or removed.
  <p>
  The scripts are expected to be under directories of the corresponding script type, for example:
  <pre>
  {@code
  (dir specified)
  ├── active
  │   ├── gof_lite.js
  │   ├── TestInsecureHTTPVerbs.py
  │   └── User defined attacks.js
  ├── extender
  │   └── HTTP Message Logger.js
  ├── httpfuzzerprocessor
  │   ├── add_msgs_sites_tree.js
  │   ├── http_status_code_filter.py
  │   └── showDifferences.js
  ├── httpsender
  │   ├── add_header_request.py
  │   └── Capture and Replace Anti CSRF Token.js
  └── variant
  └── JsonStrings.js
  }
  </pre>
  
  where {@code active}, {@code extender}, {@code httpfuzzerprocessor}, {@code httpsender}, and {@code variant} are the
  script types.
  
  @param dir the directory from where to add the scripts.
  @return the number of scripts added.
  @since 2.4.1
  @see #removeScriptsFromDir(File)