deleted limited badgeware compatibility from sec. 7

This is a small but significant change and may deserve more expanded
explanation, but here's a quick one.

The GPL has a "UI legal notice" provision (often ignored by licensors
and licensees, the subject of some past controversy in some quarters,
and the basis of Bradley Kuhn's hack for the original AGPL to boot).

One of the late changes made to GPLv3 was a modification of section 7
to make GPL-compatible additional terms requiring preservation of
author attributions not just in source code but in the UI legal notice
displayed by the running program. This change was the result of
lobbying by Larry Augustin and John Roberts (the SugarCRM founder, not
the person who later became Chief Justice of the United States). Those
familiar with free software legal history will recall that around this
time there was considerable controversy over the so-called
"attribution licenses" in use by companies like SugarCRM and
Socialtext. These licenses, labeled "badgeware licenses" by their
critics, typically required the licensee to preserve a prominent
display of the logo of the original commercial licensor even where the
licensee had made modifications (and even in contexts where compliance
with such a requirement would not be possible).

The late change made to GPLv3, accompanied by a factored-out
definition of "Appropriate Legal Notices", was not intended to allow
badgeware as then practiced, but rather a lesser form of badgeware:
for example, preservation of a "powered by" logo (with a requirement
to link back to the original licensor's website), to the extent it was
a reasonable author attribution requirement, could be a
GPLv3-compatible condition, though the FSF never intended to authorize
licensors to limit discretion over how the licensee might opt to
comply with the Appropriate Legal Notices requirement, including any
permitted lesser badgeware requirement.

A number of companies took advantage of this feature of GPLv3 (and
AGPLv3). It is now clear that it was a policy error to authorize
limited badgeware. It is my impression that companies have tended to
abuse this feature, imposing requirements more restrictive than I
believe the FSF ever intended, and it is not even entirely clear that
the logo preservation requirements are truly reasonable author
attribution requirements.

The minimum change made here is to remove the explicit authorization
of additional requirements to preserve author attributions in
Appropriate Legal Notices.
deleted definition of License; removed regeneration clause from definition of Corresponding Source

This commit makes two small changes. First, the explicit definition of
"License" is deleted as *probably* unnecessary. In GPLv2 the general
understanding has been that "License" obviously means GPLv2. Now I
recall that adding an explicit definition of "License" in GPLv3 (which
I believe was my idea) did serve some purpose other than
hyperlegalism. I believe it may have been thought desirable to clarify
that in *any* version of the GNU GPL "this License" cannot mean "some
or all versions of the GNU GPL" except in the special case of the
"revised versions" provision. (As a concrete example, consider the
meaning of GPLv2 section 2 for a "GPLv2 only" program: if "this
License" could mean "any version of the GPL", it would frustrate the
expectations of the licensors of the GPLv2-only program that modified
versions be licensed only under GPLv2 and not GPLv3 or some other
version.) Perhaps this should be revisited, but there is essentially
no basis in real-world experience that justifies the specific fear
that would motivate this clarification.

Admittedly, the GNU GPL family is unusual as a copyleft license that
does not have a built-in "or later" clause, and perhaps this feature
or non-feature (clearly important to many GPL licensors of existing
projects, such as the Linux kernel) justifies the clarification about
what "this License" means. Nevertheless in five years of experience of
GPLv2 no one has attempted to argue that because "License" is
undefined in GPLv2 one can license out a modified version of a
GPLv2-only program under GPLv3. (The counterargument to that may be
that GPLv3 retroactively provides that clarification for GPLv2.)

The second change in this commit is deletion of the following
paragraph from the definition of Corresponding Source:

  The Corresponding Source need not include anything that users can
  regenerate automatically from other parts of the Corresponding
  Source.

This must have been added for a reason, but I do not believe there is
any record of it. I do not believe I was involved in discussing or
drafting it (it seems likely that it was triggered by a stet
comment). I'm sure there is some technical circumstance in which this
sentence will provide some marginally desirable clarification of the
limits of the Corresponding Source requirement but it is not obvious
to me what such a circumstance would be. The definition of
Corresponding Source is already complex enough. GPLv2 has gotten by
without this clarification. In my post-2007 experience of GPLv3 I have
never been aware of any issue triggering this clause. In the interest
of brevity and simplification I have decided to delete it. If someone
would like to explain what it is aimed at and why explicit inclusion
of the clause is more helpful than hurtful (in making the
Corresponding Source definition more complex) I'm all ears.
deleted separable-portion clause from section 6

This commit deletes from section 6 the following paragraph:

  A separable portion of the object code, whose source code is
  excluded from the Corresponding Source as a System Library, need not
  be included in conveying the object code work.

I do not recall the reason for inclusion of this clause, though it may
have been a response to a stet comment. It is a bit strange in that
(the first half of) section 6 is concerned with the requirement to
convey Corresponding Source triggered by the action of conveying an
object code version of a work, yet this clause reads like a
clarification of a requirement to convey the object code. Of course
there is no requirement to convey object code.

What I suppose this clause must be saying is that where the
distributor ordinarily would not be conveying the System Library with
its object code work, the fact that one is required to convey
Corresponding Source (modulo System Libraries) does not somehow then
imply a requirement to convey the object code System Library. I can't
see how anyone would reasonbly think this could possibly be a
requirement in a provision that says nothing otherwise about a
requirement to provide object code.
deleted last clause of sec. 1; unnecessary given deletion of entity transactions provision
simplified title of sec. 3
simplified "void" clause of sec. 8
greatly simplified acceptance provision
deleted unnecessary T&C delimiters
deleted MS coupon provision
modified final sentence of sec. 7
deleted section 17
fixed typo in title of sec. 13
Modified README.md, mainly to de-personalize it