Add padding around `trac-content`, such as wiki page content. The padding is 19px, which is the same as the Bootstrap `well` class. Refs #306. Thanks to James (mudri) for the patch.

git-svn-id: https://svn.apache.org/repos/asf/bloodhound/trunk@1513032 13f79535-47bb-0310-9956-ffa450edef68