A clean+vanilla Ubuntu 12.04.3 desktop (new preseed.cfg + sane Vbox default settings + comments)

Reorganize preseed.cfg based on precise example+documentation

Mess with partitioning and change disk size (smaller) to 10GB

Improve VirtualBox default settings and document (also grow disk a little)

Cleanup cruft
Merge pull request #812 from mediadoneright/ubuntu-12.04.3-desktop-i386

Template: clean+vanilla Ubuntu 12.04.3 desktop