add firefox extension template

externs/ts/Tuple2.hx

@@ -0,0 +1,16 @@
+package ts;
+
+/**
+	Tuple type implementation generated by dts2hx
+**/
+@:forward @:forwardStatics extern abstract Tuple2<T0, T1>(std.Array<Any>) from std.Array<Any> to std.Array<Any> {
+	public inline function new(element0:T0, element1:T1) {
+		this = [element0, element1];
+	}
+	public var element0(get, set) : T0;
+	inline function get_element0():T0 return cast this[0];
+	inline function set_element0(v:T0):T0 return cast this[0] = cast v;
+	public var element1(get, set) : T1;
+	inline function get_element1():T1 return cast this[1];
+	inline function set_element1(v:T1):T1 return cast this[1] = cast v;
+}