Merge branch 'cal/colors' of https://github.com/t-8ch/util-linux

* 'cal/colors' of https://github.com/t-8ch/util-linux:
  cal: convert existing highlight logic to color lib
  lib/colors: introduce color_get_disable_sequence()
  cal: use escape codes from color-names.h
  cal: add test for vertical week color
  cal: add test for vertical colors