error-only for http-server, better parameter parsing for sketch markup

docs/js/custom-element/api/graphics-api.js

@@ -138,19 +138,6 @@ class GraphicsAPI extends BaseAPI {
     points.forEach((p) => this.movable.push(p));
   }
 
-  /**
-   * Get a parameter specified via data-attribute
-   */
-  getParameter(name, fallback) {
-    let val = this.dataset[name];
-    if (val) {
-      let asFloat = parseFloat(val);
-      if (val == asFloat) return asFloat;
-      return val;
-    }
-    return fallback;
-  }
-
   /**
    * Set up a slider to control a named, numerical property in the sketch.
    *