Requirements
------------
Heads build requires pretty standard GNU/Linux install with few
additional tools. On GNU/Linux Debian, you should do:
  # apt-get install vitualbox squashfs-tools git genisoimage syslinux

Build
-----
Download Tails ISO image to upstream/ folder and make sure the filename
matches the UPSTREAM_ISO_NAME variable in the Makefile. Currently the
make command has to be executed with superuser privileges, thus do
  $ sudo make setup
to unpack the Tails image into work/ (automatically created). Then
  $ sudo make chroot
to make changes to the image. Finally, do
  $ sudo make image
to build the new ISO from the working dir. ISO should appear as
heads-TIMESTAMP.iso.

Known issues
------------
WIP