ARM:Rename ARM_BIG_PAGE to ARM_SECTION.

The natural term to use when talking about MINIX big pages on ARM
is SECTION. A section is a level 1 page table entry pointing to
a 1MB area.

Change-Id: I9bd27ca99bc772126c31c27a537b1415db20c4a6
build:Updated proto.dev from mkproto -s /dev

proto.dev was missing some entries and is currently used as base version for
the ARM root file system.
tty: non-overlapping code for FKEY_CONTROL

	. to decode it in kernel/debug.c

Change-Id: I0d2cc66e87d97a362fa549b364b4d1b0e1225e66
kernel ipc debug: various fixes

	. add receive hooks in the kernel to print asynchronously
	  delivered messages
	. do not rely on MF_REPLY_PEND to decide between calls and errors,
	  as that isn't reliable for asynchronous messages; try both instead
	. add _sendcall() that extract-mfield.sh can then reliably recognize
	  the fields for messages that are sent with just send()
	. add DEBUG_DUMPIPC_NAMES to restrict printed messages to
	  from/to given process names

Change-Id: Ia65eb02a69a2b58e73bf9f009987be06dda774a3
libsys: panic hook feature

	. vfs: use it to dump threads stacks

Change-Id: I7ae3521fc153a407505f11049629e6d4142cf7c7
kernel, random: adaptive entropy gathering

kernel: stop gathering timestamps once the bin is full per interrupt

random: once seeded, retrieve new entropy at a lower rate

Change-Id: I4ce6081d39274728d82c6889686d1650cfd5fc2e
mkfs reloaded

* restored the zone>block stuff
* generalized the support for more-than-1-block bitmaps to also deal
  with big inodes maps in small blocks
* improved pexit() to printf-like syntax; also replaced pexit() with
  err() or errx() where there are no reference to proto lines
* unified the allocation of blocks to all use alloc_block() instead
  of raw malloc half of the time
* removed the V2_ d2_ etc. prefixes which are obscure and obsolete

While here, also
* used new-form definitions, and closer to KNF style in general
* used often-built-ins such as mem* or strncpy where relevant
* pruned a fair amount of constants which are irrelevant

Thanks to Thomas V. and Lionel who did a good amount of work with the
cross-compilation stuff and made that change to be much smoother.
mkfs.mfs: various programs

Split in as many programs as needed to support various variants of MFS
Manual page updated (in mandoc format)
Merge branch 'master' of git://git.minix3.org/minix into add_thread