Issue #1909: Use rebuilt VM image for VirtualBox
Issue #1909: Install fibers globally with npm, ensure proper NODE_PATH to use it
Issue #1909: Stop updating apt-get, which is basically never useful
Issue #1909: Update vagrant base box, rebuilt with Ubuntu precise32
Merge pull request #1932 from lmorchard/vagrant-box-update

Issue #1909: Use rebuilt VM image for VirtualBox