- defined a constant for the crosshair menu entry's index to get a direct

reference out of the function code.
- Fixed: The BrainExplosions should not perform any collision detection. To
  achieve this their Damage value must be set to 0 when being spawned.
- Added a safety check to savegame versioning so that an invalid revision
  (reported as 0) will be handled without breaking savegame compatibility.


SVN r689 (trunk)

src/g_doom/a_bossbrain.cpp

@@ -190,6 +190,7 @@ static void BrainishExplosion (fixed_t x, fixed_t y, fixed_t z)
 		boom->momz = pr_brainscream() << 9;
 		boom->SetState (&ABossBrain::States[S_BRAINEXPLODE]);
 		boom->effects = 0;
+		boom->Damage = 0;	// disables collision detection which is not wanted here
 		boom->tics -= pr_brainscream() & 7;
 		if (boom->tics < 1)
 			boom->tics = 1;