Support for https://github.com/axemclion/IndexedDBShim/

Since WebSQL transactions are asynchronous and therefore IndexedDBShim cant return a IDBObjectStore object (this.store) with filled indexes (this.store.indexNames). So we wait at least 100ms to give IndexedDBShim time to fill indexes :smiley:

Related: https://github.com/axemclion/IndexedDBShim/pull/47