clarify which software needs to be installed on the VCORE virtual machine

```
CORE services and menu items require additional software packages not installed
on the virtual machine. A minimum amount of software is included on the VM in
order to save space and minimize download time.

A script or written instructions could be provided for easily installing the
extra packages via apt-get.

Example missing packages:
xorp
bird
wireshark
tshark
apache2
isc-dhcp-server
nrlolsr
nrlsmf
ftp
radvd
openvpn

```

Original issue reported on code.google.com by `ahrenh...@gmail.com` on 16 Jul 2013 at 8:12