have <screen> and <programlisting> blocks indented by two spaces

have <screen> and <programlisting> blocks indented by two spaces

Define %indent-programlisting-lines% and %indent-screen-lines% to be
two spaces for both the print and html generated text styles
  <style-specification id="print|html"

after which I get a stack overflow when pulling in the GPL licence text,
so import into a <literallayout> section instead of a <screen>