-reordered sector_t so that the internal declarations are at the top, followed by the member variables and the methods.

Also tried to sort them by renderer use but that turned out to be without any performance effect, even though the struct is a bit better aligned now and several bytes shorter.

src/tarray.h

@@ -586,8 +586,7 @@ public:
 };
 
 // This is only used for exposing the sector's Lines array to ZScript.
-// This also must be trivial so that sector_t remains trivial.
-// For other uses TArrayView should be preferred.
+// Unlike TArrayView, its members are public as needed by the map loader.
 
 template <class T>
 class TStaticPointedArray