Merge pull request #1 from esben/virtualbox-4.3.x

Remove hardcoding of 4.3.10 version
Use /dev/vboxdrv from host and don't bother with kernel upgrading

The Virtualbox kernel module should be installed and loaded on host, and
then mounted as volume in guest container.

Signed-off-by: Esben Haabendal <esben@haabendal.dk>