v0.0.4

• Adds List method for iterating over user uploads. Usage:

   uploads, _ := c.List(context.Background())
  
   for {
   	u, err := uploads.Next()
   	if err != nil {
   		if err == io.EOF {
   			break // finished successfully
   		}
   		panic(err)
   	}
   	fmt.Printf("%s	%s	Size: %d	Deals: %d	Pins: %d\n", u.Created.Format("2006-01-02 15:04:05"), u.Cid, u.DagSize, len(u.Deals), len(u.Pins))
   }