Added section header to integration chapter.
Added section header to integration chapter.

ecohealthalliance/tangelo,ecohealthalliance/tangelo,ecohealthalliance/tangelo,mathstuf/tangelo,Kitware/tangelo,Kitware/tangelo,Kitware/tangelo,aashish24/tangelo,aashish24/tangelo,mathstuf/tangelo,mathstuf/tangelo,aashish24/tangelo