Support array result

whisk/action.go

diff --git a/whisk/action.go b/whisk/action.go
index 5396568..3673236 100644
--- a/whisk/action.go
+++ b/whisk/action.go
@@ -287,8 +287,8 @@
 	return resp, nil
 }
 
-func (s *ActionService) Invoke(actionName string, payload interface{}, blocking bool, result bool) (map[string]interface{}, *http.Response, error) {
-	var res map[string]interface{}
+func (s *ActionService) Invoke(actionName string, payload interface{}, blocking bool, result bool) (interface{}, *http.Response, error) {
+	var res interface{}
 
 	// Encode resource name as a path (with no query params) before inserting it into the URI
 	// This way any '?' chars in the name won't be treated as the beginning of the query params

whisk/activation.go

diff --git a/whisk/activation.go b/whisk/activation.go
index fdbe40c..8579ffa 100644
--- a/whisk/activation.go
+++ b/whisk/activation.go
@@ -61,7 +61,7 @@
 	Result     *Result `json:"result,omitempty"`
 }
 
-type Result map[string]interface{}
+type Result interface{}
 
 type ActivationListOptions struct {
 	Name  string `url:"name,omitempty"`