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:
misc/R-pillar: Update to 1.2.1

Changes:

    - Turned off using subtle style for digits that are considered
      insignificant. Negative numbers are shown all red. Set the new
      option pillar.subtle_num to TRUE to turn it on again (default:
      FALSE).

    - The negation sign is printed next to the number again.

    - Scientific notation uses regular digits again for exponents.

    - Groups of three digits are now underlined, starting with the fourth
      before/after the decimal point. This gives a better idea of the
      order of magnitude of the numbers.

    - Logical columns are displayed as TRUE and FALSE again.

    - The decimal dot is now always printed for numbers of type
      numeric. Trailing zeros are not shown anymore if all displayed
      numbers are whole numbers.

    - Decimal values longer than 13 characters always print in
      scientific notation.

    - New styling helper style_subtle_num(), formatting depends on the
      pillar.subtle_num option.

Log message:
misc/R-pillar: Import version 1.1.0

Provides a 'pillar' generic designed for formatting columns of data
using the full range of colours provided by modern terminals.