feat(collections): add new collection APIs, iterator support, and tree serialization utilities

ts/classes.stringmap.ts

@@ -31,11 +31,7 @@ export class Stringmap {
    * removes a string from Stringmap
    */
   removeString(stringArg: string) {
-    for (const keyArg in this._stringArray) {
-      if (this._stringArray[keyArg] === stringArg) {
-        this._stringArray.splice(parseInt(keyArg), 1);
-      }
-    }
+    this._stringArray = this._stringArray.filter(s => s !== stringArg);
     this.notifyTrigger();
   }