stringtable: Destroy strings before the set containing them

So that they can remove themselves from the set,

src/script/C4StringTable.cpp

@@ -176,7 +176,6 @@ C4StringTable::~C4StringTable()
 	}
 #endif
 	assert(Set.GetSize() == P_LAST);
-	for (unsigned int i = 0; i < P_LAST; ++i) P[i].Data.Clear();
 }
 
 C4String *C4StringTable::RegString(StdStrBuf String)

src/script/C4StringTable.h

@@ -264,10 +264,13 @@ public:
 	// Find existing C4String
 	C4String *FindString(const char *strString);
 
-	C4String P[P_LAST];
 private:
 	C4Set<C4String *> Set;
 	friend class C4String;
+
+public:
+	// After the set, so these are destroyed with the set still alive
+	C4String P[P_LAST];
 };
 
 extern C4StringTable Strings;