createStoreWith without middleware fails

If you call `$ngReduxProvider.createStoreWith` without specifying middleware, then `$ngRedux` will throw `Cannot read property 'Symbol(Symbol.iterator)' of undefined` upon injection.

Proposed fix: make `$ngReduxProvider.createStoreWith` take `[]` as default parameter for middleware.

Should I make a pull request?

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Chrome 44.0.2403.157
