Merge branch 'ab/generate-command-list'

Build optimization.

* ab/generate-command-list:
  generate-cmdlist.sh: don't parse command-list.txt thrice
  generate-cmdlist.sh: replace "grep' invocation with a shell version
  generate-cmdlist.sh: do not shell out to "sed"
  generate-cmdlist.sh: stop sorting category lines
  generate-cmdlist.sh: replace for loop by printf's auto-repeat feature
  generate-cmdlist.sh: run "grep | sort", not "sort | grep"
  generate-cmdlist.sh: don't call get_categories() from category_list()
  generate-cmdlist.sh: spawn fewer processes
  generate-cmdlist.sh: trivial whitespace change
  command-list.txt: sort with "LC_ALL=C sort"