Create extended shell install script and update existing installation scripts

Created an install.sh file that bundles the basic Arch packages required to
run rvm, ruby, git and ssh-dependent commands. It installs package-query and
yaourt, and a lot of system tools I use. It does NOT install the window manager
nor the loader I use as these are not required by my working environment. The
remaining apps, Gnome/Xfce, GDM and all tools that help managing the machine
should be chosen based on the configuration. For installation instructions
visit http://wiki.archlinux.org.