package: add enscript

GNU Enscript is a free replacement for Adobe's enscript program.
GNU Enscript converts ASCII files to PostScript, HTML, or RTF and
stores generated output to a file or sends it directly to the
printer. It includes features for `pretty-printing' (language-
sensitive code highlighting) in several programming languages.

[Peter: fix Config.in indentation]
Signed-off-by: Olivier Schonken <olivier.schonken@gmail.com>
[yann.morin.1998@free.fr: space-damage, unneeded variables, licensing terms]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>