templates: Removes obsolete Arch Linux templates.

Arch Linux now only provides one install media for i686 and x86_64.
"Media containing the [core] repository are no longer provided."
Essentially, there is only netboot. See
https://www.archlinux.org/news/install-media-20120715-released/

However, removing the netboot templates as x86_64 seems to be the most
up to date Arch template.
templates: Cleans up Arch Linux x86_64 definition.

This includes updating the root password to veewee instead of vagrant as
the main user should be veewee.
templates: Splits up Arch Linux postinstall{,2}.sh.

This includes a reboot step so that we don't have to work inside the
chroot the entire time.
templates: Adds ruby to Arch Linux.
templates: Adds puppet to Arch Linux.
templates: Adds chef to Arch Linux.
templates: Updates Pacman's mirrors using reflector.

Reflector will select mirrors based on last updated and download rate
which should result in faster package downloads.
templates: Allows Pacman's mirrors to be configured.

The definition now allows overriding the parameters passed to reflector.
I used this to pass in Australian, New Zealand mirrors to speed up
downloads. For example,
--verbose -c "New Zealand" -c Australia -n 5 --sort rate --save \
/etc/pacman.d/mirrorlist
templates: Adds a final reboot before cleanup.

A final reboot is necessary for veewee vbox validate for shared folders
to pass (this is when running veewee vbox validate directly after
building the box).
templates: Installs Ruby 1.9 on Arch Linux, not 2.0.

Chef does not support Ruby 2.0 yet.
templates: Change TMPDIR for Packer.
templates: Fixes Arch's failing network on reboot.
templates: Gets the latest ISO in the Arch definition.

The method used is similar to that used in the Gentoo templates.
templates: Adds README for Arch x86_64 template.

The provided info can be used to speed up building of the box.
Merge pull request #689 from anshumanb/arch-templates

Arch Linux templates update