Wrap http.Response in Response struct

The Response struct has StartAt, MaxResults and Total fields, which are
returned from JIRA API in issue search responses. They are now
accessible in Response object.

jira_test.go

@@ -296,3 +296,24 @@ func TestGetBaseURL_WithURL(t *testing.T) {
 		t.Errorf("Base URLs are not equal. Expected %+v, got %+v", *u, b)
 	}
 }
+
+func TestPagingInfoEmptyByDefault(t *testing.T) {
+	c, _ := NewClient(nil, testJIRAInstanceURL)
+	req, _ := c.NewRequest("GET", "/", nil)
+	type foo struct {
+		A string
+	}
+	body := new(foo)
+
+	resp, _ := c.Do(req, body)
+
+	if resp.StartAt != 0 {
+		t.Errorf("StartAt not equal to 0")
+	}
+	if resp.MaxResults != 0 {
+		t.Errorf("StartAt not equal to 0")
+	}
+	if resp.Total != 0 {
+		t.Errorf("StartAt not equal to 0")
+	}
+}