Installing posix tests in /usr/tests/minix-posix

The goal is to enable anyone to simply run our current test suite.

Change-Id: I27d8856cb82a4be2baa5dc5273526383b7f4fc2c
Install default users directly

Install /home/ast and /home/bin as part of the system build procedure,
as the setup script is not ran on the arm image.

/home/bin is needed for successful completion of our test suite.

This patch does not change the setup script, as it is not bothered by
those files/directiories being already there, and may be useful during
reinstallation on intel systems.

Change-Id: I358c881df09223c343442673aa0822937f9ea33c
VM: pagequeue data structure

	. data structure that automatically keeps a set
	  of pages in reserve, to replace sparepages and
	  possibly re-used in the future for similar situations,
	  e.g. if in-filesystem-cache block eviction is
	  implemented and FS asks for a new block

Change-Id: I149d46c14b9c8e75df16cb94e08907f008c339a6
VM: pagetable.c: harmonize x86/ARM findhole() code

ARM needs to be able to find N consecutive free slots; use same
code for x86.

Change-Id: Ic79677961c8adfca2aeb5385962942ae0d76867c
Adapt ARM print macro to match used types

Change-Id: I987c669dce30d97ff67e33a50106a07163f7d7f1
Change the group of ast to users instead of others

Change-Id: I3c92554f209fa39597e55a6b407dddd447111f2f
Importing bin/ksh
VM: ARM/I386 PDE/PTE macro unification

	. further reduces special cases in pagetable.c

Change-Id: Ifd7dd9ee10ca618a47bb4a372467205fbe6da90e
Importing usr.bin/who
Importing usr.bin/yes

Change-Id: Ia76d7ce9c6b2bf7523d2ecbc6470e3e1e7ab5ee5
Importing usr.bin/cal
packages.install: remove obsolete minix-all pkg.

The minix-all package was placed by the pkgin_all command.
release.sh: pkg_install should be installed 1st

pkgin now depends on pkg_install. If pkg_install appears after pkgin
in PREINSTALLED_PACKAGES, there will be an error because pkg_install
was installed as a dependency for pkgin.
Rename "struct partition" to "struct part_geom"

Change-Id: Ifaf9795ba70f5b933599b2a6ec9415e6bd13200c
Move MINIX reboot definitions into minix/reboot.h

Also fix a buffer overflow in commands/reboot/sh_wall.c.

Change-Id: I3a61057c4f0221d1700e14d44520b4ad17f1dbe1
vfs: coredump fix: write zeroes for missing memory
VFS: wikify README

Change-Id: I746f7c8ddabd1e047b8d536df14586c5b1594d55