Add padding to EmailSchedEvent struct.

Specialisations of SchedEvent must be at least as large as a SchedEvent otherwise we get a buffer overrun when trying to copy it into the schedule queue.

Author: icosahedral-dragon

Diff for: src/GameSrc/Headers/trigger.h

@@ -83,6 +83,7 @@ typedef struct _EmailSchedEvent {
     ushort timestamp;
     ushort type;
     short datamunge;
+    short pad; // must be at least as big as a SchedEvent
 } EmailSchedEvent;
 
 // Prototypes