Log message:
graphics: Replace RMD160 checksums with BLAKE2s checksums

All checksums have been double-checked against existing RMD160 and
SHA512 hashes

Log message:
graphics: Remove SHA1 hashes for distfiles

Log message:
(graphics/R-munsell) Add one TEST_DEPENDS+=

Log message:
Update all R packages to canonical form.

The canonical form [1] of an R package Makefile includes the
following:

- The first stanza includes R_PKGNAME, R_PKGVER, PKGREVISION (as
  needed), and CATEGORIES.

- HOMEPAGE is not present but defined in math/R/Makefile.extension to
  refer to the CRAN web page describing the package.  Other relevant
  web pages are often linked from there via the URL field.

This updates all current R packages to this form, which will make
regular updates _much_ easier, especially using pkgtools/R2pkg.

[1] http://mail-index.netbsd.org/tech-pkg/2019/08/02/msg021711.html

Log message:
Remove MASTER_SITES= from individual R package Makefiles.

Each R package should include ../../math/R/Makefile.extension, which also
defines MASTER_SITES.  Consequently, it is redundant for the individual
packages to do the same.  Package-specific definitions also prevent
redefining MASTER_SITES in a single common place.

Log message:
graphics/R-munsell: Import version 0.4.3

Provides easy access to, and manipulation of, the Munsell
colours. Provides a mapping between Munsell's original notation
(e.g. "5R 5/10") and hexadecimal strings suitable for use directly in
R graphics. Also provides utilities to explore slices through the
Munsell colour tree, to transform Munsell colours and display colour
palettes.