Dropped more or less useless files

.gitattributes

-public/conf/gitignore/* linguist-vendored
-public/conf/license/* linguist-vendored
-public/assets/* linguist-vendored
-public/plugins/* linguist-vendored
-public/plugins/* linguist-vendored
-public/css/themes/* linguist-vendored
-public/css/github.min.css linguist-vendored
-public/css/semantic-2.2.1.min.css linguist-vendored
-public/js/libs/* linguist-vendored
-public/js/jquery-1.11.3.min.js linguist-vendored
-public/js/semantic-2.2.1.min.js linguist-vendored

.mailmap

-Unknwon <u@gogs.io> <joe2010xtmf@163.com>
-Unknwon <u@gogs.io> 无闻 <u@gogs.io>