Add two test file, about grid.
Add test file for data store and object store, including csvStore, memoryStore, csvStoreToObjectStore.
Add test file and data for data store: itemFileReadStore.
Add a new file: selectionGridUsingObjectStore.html, explain how to setup a gird with object store.
Add a new file: selectionGridUsingDataStore.html, explain how to setup a grid with data store.