*: Bump PORTREVISIONs for math/mpc update to 1.3.1

Remove WWW entries moved into port Makefiles

Commit b7f05445c00f has added WWW entries to port Makefiles based on
WWW: lines in pkg-descr files.

This commit removes the WWW: lines of moved-over URLs from these
pkg-descr files.

Approved by:		portmgr (tcberner)

Add WWW entries to port Makefiles

It has been common practice to have one or more URLs at the end of the
ports' pkg-descr files, one per line and prefixed with "WWW:". These
URLs should point at a project website or other relevant resources.

Access to these URLs required processing of the pkg-descr files, and
they have often become stale over time. If more than one such URL was
present in a pkg-descr file, only the first one was tarnsfered into
the port INDEX, but for many ports only the last line did contain the
port specific URL to further information.

There have been several proposals to make a project URL available as
a macro in the ports' Makefiles, over time.

math: remove 'Created by' lines

A big Thank You to the original contributors of these ports:

  *  Aaron Dalton <aaron@FreeBSD.org>
  *  Aaron Dalton <aaron@daltons.ca>
  *  Alessando Sagratini <ale_sagra@hotmail.com>
  *  Alex Dupre <ale@FreeBSD.org>
  *  Alexey Dokuchaev <danfe@FreeBSD.org>
  *  Amarendra Godbole <amarendra.godbole@gmail.com>
  *  Anders Nordby <anders@FreeBSD.org>
  *  Andreas Fehlner (fehlner@gmx.de)
  *  Andrew L. Neporada <andrew@chg.ru>
  *  Andrey <gugu@zoo.rambler.ru>
  *  Andrey Zakhvatov

Remove # $FreeBSD$ from Makefiles.

- Update to 2021.1

- Update to 2020.5

- Update to 2020.4

- Update to 2020.3

math/R: Update to version 4.0.0

Upstream changes:
https://stat.ethz.ch/pipermail/r-announce/2020/000653.html

Also bump PORTREVISION of ports that depend on math/R.

Submitted by:	wen (in part)
Reviewed by:	jwb, Rainer Hurling <rhurlin@gwdg.de>, thierry
Differential Revision:	https://reviews.freebsd.org/D24572

- Update to 2020.2

- Update to 2020.1

Bump PORTREVISION for ports depending on the canonical version of GCC
as defined in Mk/bsd.default-versions.mk which has moved from GCC 8.3
to GCC 9.1 under most circumstances now after revision 507371.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, everything INDEX-11 shows with a dependency on lang/gcc9 now.

PR:		238330

Bump PORTREVISION for ports depending on the canonical version of GCC
defined via Mk/bsd.default-versions.mk which has moved from GCC 7.4 t
GCC 8.2 under most circumstances.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, as a double check, everything INDEX-11 showed depending on lang/gcc7.

PR:		231590

- Add new port: math/R-cran-SQUAREM

  Algorithms for accelerating the convergence of slow, monotone
  sequences from smooth, contraction mapping such as the EM algorithm.
  It can be used to accelerate any smooth, linearly convergent
  acceleration scheme. A tutorial style introduction to this package
  is available in a vignette on the CRAN download page or, when the
  package is loaded in an R session, with vignette("SQUAREM").

  WWW: https://cran.r-project.org/web/packages/SQUAREM/