Added game.add.plugin to the definitions file

Author: alvinsight

build/phaser.d.ts

@@ -2061,6 +2061,7 @@ declare module Phaser {
         group(parent?: any, name?: string, addToStage?: boolean, enableBody?: boolean, physicsBodyType?: number): Phaser.Group;
         image(x: number, y: number, key: any, frame?: any, group?: Phaser.Group): Phaser.Image;
         physicsGroup(physicsBodyType: number, parent?: any, name?: string, addToStage?: boolean): Phaser.Group;
+        plugin(plugin: Phaser.Plugin, ...parameter: any[]): Phaser.Plugin;
         renderTexture(width?: number, height?: number, key?: string, addToCache?: boolean): Phaser.RenderTexture;
         retroFont(font: string, characterWidth: number, characterHeight: number, chars: string, charsPerRow: number, xSpacing?: number, ySpacing?: number, xOffset?: number, yOffset?: number): Phaser.RetroFont;
         sound(key: string, volume?: number, loop?: number, connect?: boolean): Phaser.Sound;