add Extension config keys:freemarker.auto_scan_packages
Merge pull request #1 from subchen/master

合并SUBCHEN的FreeMarker支持
Merge branch 'master' of https://github.com/andydmx/jetbrick-webmvc
Merge pull request #1 from andydmx/master

为Jetbrick MVC Freemarker增加包自动扫描功能