Introduce networking for the interim VM and fix some smaller issues

By activating networking for the interim VM the installer script can actually fetch external bits for the post installation process.

I switched to use the FreeBSD-10.0-RELEASE-amd64-disc1.iso because it serves all distributions that are needed for the installation and saves about 2G bandwidth.

The me-freebsd repository is integrated via an additional distribution package.


notes:
The bundled mdata-get in the me-freebsd repository fails to execute on the created FreeBSD installation. Also this should be replaced by the mdata-client toolset.