Add gitter chat badge.
add handling for packages by yaourt, based on that of pacman
yaourt uses pacman, so should depend on pacman-update, not its own
yaourt should not be run as root: it uses sudo as necesary itself
pacman, yaourt should only check for native, foreign packages respectively
brew-update should depend on brew, which should depend on osx
python can be installed with pacman
python: assume the equivalent of build-essential has been met
don't automatically update homebrew, apt, pacman, yaourt
extended marelle to reduce needed platform logic in deps files
made 04-apt.pl resemble 08-pacman.pl
updated 08-pacman.pl to be closer to 04-apt.pl
updated 09-yaourt.pl to resemble 08-pacman.pl, reference aur, not yaourt
added various helper functions
10-exts: fixed debian_pkg/2
added function to assist not-in-marelle
included functionality of not-in-marelle
marelle missing should check all explicitly installed packages, even those who are a dependency of another package
'marelle undefined' returns 1 if all of the arguments given are defined as a package in marelle
fixed typo