Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Update to SDM 2.2:
o Add tf (test feature) instruction,
o Add vmsw (VM switch) instruction.

While here, update copyright.

MFC after: 1 week

Sync up with SDM 2.1:
o Add nop/hint formats F16, I18, M48 and X5,
o Add format M47 for ptc.e,
o Add hint instruction,
o Fix decoding of cmp8xchg16.

/* -> /*- for copyright notices, minor format tweaks as necessary

Add a new disassembler that improves over the previous disassembler
in that it provides an abstract (intermediate) representation for
instructions. This significantly improves working with instructions
such as emulation of instructions that are not implemented by the
hardware (e.g. long branch) or enhancing implemented instructions
(e.g. handling of misaligned memory accesses). Not to mention that
it's much easier to print instructions.

Functions are included that provide a textual representation for
opcodes, completers and operands.

The disassembler supports all ia64 instructions defined by revision
2.1 of the SDM (Oct 2002).