rmgen cleanup.

Remove initTerrain from Map, because that class should only have getters
and setters, refs #4804.
Unify it with the global initTerrain function.
Remove some redundant calls to that.

This was SVN commit r20386.

binaries/data/mods/public/maps/random/african_plains.js

@@ -54,8 +54,6 @@ var clMetal = createTileClass();
 var clFood = createTileClass();
 var clBaseResource = createTileClass();
 
-initTerrain(tPrimary);
-
 var [playerIDs, playerX, playerZ] = radialPlayerPlacement();
 
 for (var i = 0; i < numPlayers; ++i)

binaries/data/mods/public/maps/random/african_plains.json

@@ -3,7 +3,7 @@
 		"Name" : "African Plains",
 		"Script" : "african_plains.js",
 		"Description" : "The central region of the vast continent of Africa, birthplace of humanity. Players start in a lush area teeming with vegetation and wildlife.",
-		"BaseTerrain" : ["medit_sea_depths"],
+		"BaseTerrain" : ["savanna_grass_a"],
 		"BaseHeight" : 2,
 		"Keywords": [],
 		"Preview" : "african_plains.png",

binaries/data/mods/public/maps/random/arctic_summer.js

@@ -53,8 +53,6 @@ var clMetal = createTileClass();
 var clFood = createTileClass();
 var clBaseResource = createTileClass();
 
-initTerrain(tPrimary);
-
 var [playerIDs, playerX, playerZ] = radialPlayerPlacement();
 
 for (let i = 0; i < numPlayers; i++)

binaries/data/mods/public/maps/random/arctic_summer.json

@@ -3,7 +3,7 @@
 		"Name" : "Arctic Summer",
 		"Script" : "arctic_summer.js",
 		"Description" : "Summer has arrived to the cold regions of the north and with it have many animals, profiting from its milder climate. Wolves, ever present, have shed their winter clothes; deer, hares and muskox populate the plains. The last traces of winter are rapidly disappearing, only to reappear very soon.",
-		"BaseTerrain" : ["medit_sea_depths"],
+		"BaseTerrain" : ["alpine_grass_rocky"],
 		"BaseHeight" : 2,
 		"Keywords": [],
 		"Preview" : "arctic_summer.png",

binaries/data/mods/public/maps/random/polar_sea.js

@@ -45,8 +45,6 @@ var clWolf = createTileClass();
 // Expected by rmgen1
 var clForest = createTileClass();
 
-initTerrain(tPrimary);
-
 var [playerIDs, playerX, playerZ] = radialPlayerPlacement();
 
 RMS.SetProgress(20);

binaries/data/mods/public/maps/random/polar_sea.json

@@ -3,7 +3,7 @@
 		"Name" : "Polar Sea",
 		"Script" : "polar_sea.js",
 		"Description" : "Players start in a cold polar region barren of vegetation. In the sea fish and whales abound, while the fragile icy land teems with huntable walruses and deadly wolves. These wolves, made ravenous by the harsh and forbidding climate, drawn by the scent of prey, have started appearing in terrifying numbers. A wise and strong ruler will not only achieve victory over his enemies, but also keep the number of these beasts at bay, lest they undermine his economy and cause his downfall. [color=\"red\"]Warning: It is inadvisable to disable treasures, since there is no gatherable wood. Not recommended for inexperienced players.[/color]",
-		"BaseTerrain" : ["medit_sea_depths"],
+		"BaseTerrain" : ["polar_snow_a"],
 		"BaseHeight" : 2,
 		"Keywords": ["trigger"],
 		"Preview" : "polar_sea.png",

binaries/data/mods/public/maps/random/rmgen/library.js

@@ -288,9 +288,13 @@ function placeTerrain(x, z, terrain)
 	g_Map.placeTerrain(x, z, createTerrain(terrain));
 }
 
-function initTerrain(terrain)
+function initTerrain(terrainNames)
 {
-	g_Map.initTerrain(createTerrain(terrain));
+	let terrain = createTerrain(terrainNames);
+
+	for (let x = 0; x < getMapSize(); ++x)
+		for (let z = 0; z < getMapSize(); ++z)
+			terrain.place(x, z);
 }
 
 function isCircularMap()

binaries/data/mods/public/maps/random/rmgen/map.js

@@ -58,13 +58,6 @@ function Map(size, baseHeight)
 	this.entityCount = 150;
 }
 
-Map.prototype.initTerrain = function(baseTerrain)
-{
-	for (let i = 0; i < this.size; ++i)
-		for (let j = 0; j < this.size; ++j)
-			baseTerrain.place(i, j);
-};
-
 /**
  * Returns the ID of a texture name.
  * Creates a new ID if there isn't one assigned yet.

binaries/data/mods/public/maps/random/rmgen/mapgen.js

@@ -29,7 +29,7 @@ function InitMap()
 
 	log("Creating new map...");
 	g_Map = new Map(g_MapSettings.Size, g_MapSettings.BaseHeight);
-	g_Map.initTerrain(createTerrain(g_MapSettings.BaseTerrain));
+	initTerrain(g_MapSettings.BaseTerrain);
 }
 
 function ExportMap()