修改composer为国内镜像
composer config -g repositories.packagist composer http://packagist.phpcomposer.com
composer创建laravel项目（指定版本为4.1）
composer create-project laravel/laravel=4.1.* --prefer-dist PROJECT_NAME
更新composer版本
composer self-update
原文：http://ww123.blog.51cto.com/5559238/1696521