在执行composer update时报错
[ReflectionException]
Class FxpComposerAssetPluginRepositoryNpmRepository does not exist
是因为 fxp/composer-asset-plugin 升级导致的，所以只要升级fxp/composer-asset-plugin 就可以解决
composer global update fxp/composer-asset-plugin --no-plugins
FROM：
http://stackoverflow.com/questions/36437837/composer-throw-reflectionexception-class-fxp-composer-assetplugin-repository-n