Rename netbsdit-refcard-en to netbsdit-refcard.
Finally rename to netbsd-refcard.tex
Add the NetBSD flag image.
From http://www.netbsd.org/images/NetBSD-flag.png
Add a .gitignore in order to not import various LaTeX files.
Add a Makefile to ease the building of The NetBSD reference card (it uses
latex-mk).
Various clean-ups to the NetBSD refcard in order to succesfully build it after 6
years.