Add missing includes

inferno/src/inferno/event/joystickevent.h

@@ -1,6 +1,8 @@
 #ifndef JOYSTICKEVENT_H
 #define JOYSTICKEVENT_H
 
+#include <sstream> // std::stringstream
+
 #include "inferno/event/event.h"
 
 namespace Inferno {
@@ -51,5 +53,4 @@ namespace Inferno {
 
 }
 
-
 #endif // JOYSTICKEVENT_H

inferno/src/inferno/event/keyevent.h

@@ -1,6 +1,8 @@
 #ifndef KEYEVENT_H
 #define KEYEVENT_H
 
+#include <sstream> // std::stringstream
+
 #include "inferno/event/event.h"
 
 namespace Inferno {

inferno/src/inferno/event/mouseevent.h

@@ -1,6 +1,8 @@
 #ifndef MOUSEEVENT_H
 #define MOUSEEVENT_H
 
+#include <sstream> // std::stringstream
+
 #include "inferno/event/event.h"
 
 namespace Inferno {