[gh-423] Server Side Include of other CMS page creates HTML validation error

When using the server side include feature to bring the maincontent of another page inside the UNL CMS, it also grabs extra markup: a container div id="content". Since the parent page already has this div, it introduces a duplicate id error.

Example page: http://unlcms.unl.edu/office-of-university-communications/college-of-architecture/programs/architecture/bachelor-science-design

Proposed fix: Don't bring the extra-markup of the child page.