* For consistency with other lexers, like the C/C++ lexer.
* `^*`, `^/` and `^#` are also true operators and shouldn't be styled
  as regular commands.
  This required introducing a new operator style (3).

* color.target is yellow in terminal.tes which looks awful and it should be
  used sparingly.
  The largest part of text in any lexer should be in the default colors.
* bash.tes now discerns between double and single quote strings like most lexers.
* autodetect GNUmakefiles
* yaml.tes now uses color.string for keys - this is for consistency with JSON
  where keys will also always be strings.

* M[lexer.set.cmdline] can be used to set up syntax highlighting on the command line
  (if desired).
* Color schemes with light-dark themes (solarized.tes) are now responsible
  to update the command line view as well.

* This requires the new SCI_SETTABDRAWMODE(SCTD_CONTROLCHAR).
* It makes no sense to let TAB indent in TECO code as it can be
  the insert-with-tab command (^I).
  On the other hand large `I`-blocks could include TABs which are
  actually meant as indentations.

* strings are bold (if supported) and bright white
* comments are in italics (if supported by the terminal)
* otherwise this uses the same colors as terminal.tes
* should be well suited for monochrome terminals as well

This was broken by e82dc6639e829490cb11267fa4a49ef97c6459ae, i.e. wasn't broken in v2.4.0.

Hard tabs would even cause YAML syntax errors.

* They would get the --program-prefix.
* If they aren't installed as real scripts, there is no point in fixing up their
  hash-bang lines.
* The hash-bang line fix won't work on Windows anyway, so they are now disabled for
  grosciteco and tedoc as well.

A 32-bit word is enough to carry the information of which control code to echo or not.