(svn r12022) -Revert(r12018): Invisible trees are now separate from the building concept.

So when you want invisible trees, just select the option of the same name in the Patch Options and toggle transparency of trees.
More to come on the saga of Invisibility. So stay tuned.

src/tree_cmd.cpp

@@ -428,8 +428,8 @@ static void DrawTile_Trees(TileInfo *ti)
 
 	StartSpriteCombine();
 
-	/* Do not draw trees when buildings are transparent and when the invisile trees patch is on */
-	if (!(_patches.invisible_trees && IsTransparencySet(TO_HOUSES))) {
+	/* Do not draw trees when the invisible trees patch and transparency tree are set */
+	if (!(IsTransparencySet(TO_TREES) && _patches.invisible_trees)) {
 		TreeListEnt te[4];
 		uint i;