Merge branch aptitude-fix

[ioistired]

This will use heredocs and aptitude, instead of apt-get -y install $packagename for each package to be installed, meaning that apt-get doesn't have to read the package cache database for each package installation, avoiding slowdowns. So, instead of

apt-get -y install gimp
apt-get -y install krita
apt-get -y install inkscape

We can use

aptitude -y install <<-EOF
    gimp
    krita
    inkscape
EOF

The reason for using aptitude instead is that using apt-get and a heredoc would exit if a non-existent package is listed. aptitude ignores non-existent packages, however.

[SlaterByte]

We need to test this branch on a couple of fresh systems before merging. As apt-get has an --ignore-missing but not an --ignore-nonexistant, aptitude looks like the right solution. aptitude to speeds up the install process and make it cleaner. However, how can aptitude tell us when a package is no longer available? It doesn't seem to produce any standard error, even if packages aren't found.