Use strings.Fields

caste.go

diff --git a/caste.go b/caste.go
index 36f6f91..11a06fb 100644
--- a/caste.go
+++ b/caste.go
@@ -294,7 +294,7 @@
 	case []string:
 		return v, nil
 	case string:
-		return strings.Split(v, " "), nil
+		return strings.Fields(v), nil
 	default:
 		return a, fmt.Errorf("Unable to Cast %#v to []string", i)
 	}