客户端存储

客户端存储
异步操作localStorage：
uni.setStorage(key, value, success(){ }) / uni.getStorage(k, success(){ }) / uni.removeStorage(k, success(){}) / uni.clearStorage( success(){} )
同步操作localStorage：
uni.setStorageSync(k, v) / uni.getStorageSync(k) / uni.removeStorageSync(k) / uni.clearStorageSync( )