README updated

* /etc/MBR/syslinux is gone since 62b6848c451e6ec4834b7f00479c9ec443e314a3
* SYSLINUX and ArchLinux have the same range of supported platforms:
  x86 and amd64
README: s/quit/exit/ - standardese
readme had a bug (it's $software, not $packages)
example $software tweaked, commented
install apg aria2 ipython dnsmasq rpm-org qiv