Enhancement: Changed how store names are assigned.

Previous: If no store name is provided in request, default store name is used. If no default store name is provided, an error is generated.  Store name is mandatory.

Current: If no store name is provided in request, default store name is used. If not default store name is provided, layer name is used for store name. Store name is optional.
Merge pull request #3 from isuftin/master

Store name enhancement