用法示例：
import DroneClient from 'drone-js' ;
// drone server and credentials
const server = "https://drone.company.com" ;
const token = "..." ;
// creates the drone client
const client = new DroneClient ( server , token ) ;
// fetches the repository list
client . getRepoList ( ) . then ( ( repos ) => {
} ) ;
从窗口配置客户端：
window . DRONE_SERVER = "https://drone.company.com" ;
window . DRONE_TOKEN = ".
