Make get/put more robust

- init folder if not present already in 'get()' call
  - put.go was referencing wrong args - fix it
  - if no OBJECTNAME is specified during 'get' - grab a
    list of files under "~/.minio"
  - Provide new API GetList() for ObjectStorage struct

cmd/erasure-demo/get.go

@@ -14,11 +14,19 @@ func get(c *cli.Context) {
 		log.Fatal(err)
 	}
 	var objectReader io.Reader
+	objectName := c.Args().Get(0)
+
 	switch config.storageDriver {
 	case "fs":
 		{
-			if objectReader, err = fsGet(config, c.Args().Get(0)); err != nil {
-				log.Fatal(err)
+			if len(objectName) == 0 {
+				if objectReader, err = fsGetList(config); err != nil {
+					log.Fatal(err)
+				}
+			} else {
+				if objectReader, err = fsGet(config, objectName); err != nil {
+					log.Fatal(err)
+				}
 			}
 		}
 	default:
@@ -28,25 +36,3 @@ func get(c *cli.Context) {
 	}
 	io.Copy(os.Stdout, objectReader)
 }
-
-func put(c *cli.Context) {
-	config, err := parseInput(c)
-	if err != nil {
-		log.Fatal(err)
-	}
-	filePath := c.Args().Get(1)
-	inputFile, err := os.Open(filePath)
-	if err != nil {
-		log.Fatal(err)
-	}
-	switch config.storageDriver {
-	case "fs":
-		{
-			fsPut(config, c.Args().Get(0), inputFile)
-		}
-	default:
-		{
-			log.Fatal("Unknown driver")
-		}
-	}
-}