feature/typescript : add types

[bastienrobert]

Add following types:

addCamera(name: string, camera: THREE.Camera): GUI
addFog(name: string, fog: THREE.Fog | THREE.FogExp2): GUI
addLight(name: string, light: THREE.Light): GUI
addMaterial(name: string, material: THREE.Material): GUI
addMesh(name: string, mesh: THREE.Mesh, options?: { recursive?: boolean }): GUI
addScene(name: string, mesh: THREE.Scene | THREE.Object3D, options?: { recursive?: boolean }): GUI
addObject3D( name: string, mesh: THREE.Object3D, options?: { recursive?: boolean, inner?: boolean, stepPosition?: number, stepRotation?: number, stepScale?: number }): GUI
addVector(name: string, vector: THREE.Vector | THREE.Euler, options?: { step?: 0.1 }): GUI