Added product API

@czue 
Testypie returns json in format: 
```{meta:{...}, objects:[<list_of_products>]} ```

I added this because We want change response format to:
```{products_list: [<list_of_products>]} ```

In normal version of method in line 19 we have:
```options = options or {}```
I changed this to:
```options = options or {'type': self.type}```

I want use this for the all API's and in 'type' property I want keep a key for response object.

Please let me know if this is make sense.