Finish amd64 port of DragonFly

by Jordan Gordeev for DragonFly BSD

PROJECT TITLE ============= Finish amd64 port of DragonFly. DELIVERABLES ============ 1. functional amd64 port - UP kernel (mostly functional by midterm) 2. functional amd64 port - SMP kernel (mostly functional by midterm) 3. working 64-bit vkernels (after midterm) 4. working 32-bit apps on 64-bit kernel (after midterm)