[configs/releng] Add an empty machine-id

This makes systemd generate a machine-id on early boot and prevents it from thinking we need any "first boot" setup. We really don't want systemd thinking that, since we carefully prepared our root file system.

This also ensures every live environment has a unique machine id.

See: https://mailman.archlinux.org/pipermail/arch-releng/2014-September/003435.html
[configs/alter] Add an empty machine-id
prepare release
[configs/alter] install.txt: avoid redirection
[configs/alter] Toggle on numlock even in single user mode
[archiso] aitab: allow set mount options

New column in aitab, which is used for setting mount options for each filesystem.

Minor: also add a keep-ending-newline note in aitab
[configs/alter] Update README
[archiso] New boot parameter img_dev_mnt_opt

Which is used for setting the mount options of img_dev
[archiso] Disable ext4 resize_inode

Remove unused feature, just to save space

https://mailman.archlinux.org/pipermail/arch-releng/2014-August/003426.html
update README.md
[configs/alter] October update

* Set the default serial speed to 115200 bps, also add a new boot entry for this
* Restore the extra EFI support, except for the efiboot.img, which is used for "El Torito" EFI boot mode
* Use the emacs-friendly US keymap
* root-image: use ext4 instead of ext2
* New packages in packages.{backport,both}: pax, bmon, 6rdctl-git, autodkms, smp_utils, isz-tool and so on
* build.sh: add '--preserve=timestamps' to some cp command, in order to preserve the mtime
* Change the way to determine if enable NoCow(chattr +C) for btrfs pool
* Remove the empty fstab in root-image/etc
  ... and other minor fixup
[configs/alter] November update

* Add packages:
  * compton: good X11 compositor
  * hardening-wrapper: scripts for building hardened executables
  * picocom: _pico_ serial communication program
  * whowatch: watch who is doing what in real-time
  * profanity: irssi-like xmpp(jabber) client
  * xbindkeys: run command when a specificed key is pressed
  * xbrightness: control X11 display brightness
  * ee: easyedit, a text editor
  * hping
* Remove packages:
  * pax-utils
  * gpick - gcolor2 is enough for similar needs
  * minicom - don't know how to use, takes up more space than picocom
  * optipng - zopflipng provides a better compression ratio
  * sxiv,feh - gpicview provides same functionality
  * xfce4-terminal - vte is buggy, try to run: "printf '\x1bP'"(unstuck with printf '\x1b\') http://invisible-island.net/xterm/xterm.faq.html#bug_gnometerm
* Replace packages:
  * vim -> gvim - for GTK+ gui
  * syslog-ng -> rsyslog - for rsyslog's templates - to specify the format that a user want
* Other minor update:
  * vim,tmux,mc,zsh configuration
  * archiso_sys.cfg: reword - should be bps instead of baud, see http://www.tldp.org/HOWTO/Modem-HOWTO-23.html
  * autologin.conf: don't pass baud_rate and TERM to agetty specifically
  * pacman.conf: change the URL of [archlinuxcn] - use a mirror