[surun] New tool for running commands asa root

It uses sudo or su (whichever is available) to actually become root,
but thanks to automatic detection hides some differences in the way
those tools are called.

su is particularly annoying if one wants to run a command as
super-user since it requires the whole command to be escaped and
specified as shell expression.  sudo on the other hand requires
“-s” argument if one wants to run a shell.

With surun, one spawns a root shell by calling it with no arguments
(like su), and runs a command by specifying the command as arguments
(like sudo).
[pkg] A new tool for unifying various package management tools.

Depending on system one is running, pkg will run either apt-get, yum
or package management tools that come with Slackware and will
translate its semantic into whatever underlying tool requires.  It
will also run the command through sudo/surun if necessary and thus
makes it unnecessary for user to type “sudo” or whatever.