[idn] Added reference, and synch. of terminology

[Karlsson Kent - keka <keka@im.se>]

For increased mutual understandability, I suggest the following:

Both the requirements document and other IDN documents should
refer to Unicode Technical Report 17, Character Encoding Model
(http://www.unicode.org/unicode/reports/tr17/). Perhaps also to W3C's
Character Model for the World Wide Web (http://www.w3.org/TR/charmod/).
The terminology used in the IDN requirements document, comparison
document, and others should be aligned with the terminology
defined in UTR 17.  Thus, e.g., "ACE" to "TES" (Transfer Encoding
Syntax); and all of RACE, UTF-5 (and UTF-7), "hex of UTF-8", and
many other proposals are or include TESes (i.e. they are not UTFs,
despite the name of some of them).  The requirements document
should also give a short summary of the five terms defined in
UTR 17.  It should also point out that the IETF notion of "charset"
is not well-defined, and that two TESes (BASE64 and QP) are
singled out and not included in "charset", but any other CES+TES
is regarded as a "charset".

The requirements document should also point out that the use
of TESes may pose problems over and above the use of CESes,
like risk for lack of decode of the (chosen) TES even within
special applications, and total lack of decode (of any TES)
outside of certain portions of special applications.

		Kind regards
		/kent k