Fix xenmaker crashing when many of them are activated simultaneously.

src/dlls/monster_plugin.h

@@ -30,7 +30,7 @@ typedef struct
    CMBaseMonster *pMonster;
 } monster_t;
 
-#define MAX_MONSTER_ENTS 400
+#define MAX_MONSTER_ENTS 512
 
 extern monster_t monsters[MAX_MONSTER_ENTS];
 
@@ -43,7 +43,7 @@ typedef struct {
    bool need_to_respawn;
 } monster_spawnpoint_t;
 
-#define MAX_MONSTERS 200
+#define MAX_MONSTERS 256
 extern monster_spawnpoint_t monster_spawnpoint[MAX_MONSTERS];
 
 // this is here to store if a node we want to spawn is an ordinary one, or a flying one