Remove references to GameMath, it's just Math now

Throw exceptions if wrong format given to tilemap or textureatlas. Previously, old onload remained active and error happened in the wrong (and hard to diagnose) place.

src/loader/Loader.js

@@ -744,6 +744,10 @@ Phaser.Loader.prototype = {
 						return _this.csvLoadComplete(file.key);
 					};
 				}
+				else
+				{
+					throw new Error("Phaser.Loader. Invalid Tilemap format: " + file.format);
+				}
 
 				this._xhr.onerror = function () {
 					return _this.dataLoadError(file.key);
@@ -873,6 +877,10 @@ Phaser.Loader.prototype = {
 							return _this.xmlLoadComplete(file.key);
 						};
 					}
+					else
+					{
+						throw new Error("Phaser.Loader. Invalid Texture Atlas format: " + file.format);
+					}
 
 					this._xhr.onerror = function () {
 						return _this.dataLoadError(file.key);
@@ -1105,4 +1113,4 @@ Phaser.Loader.prototype = {
 
 	}
 
-};
+};