* 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.

* Set up the folding margin in the currently empty margin column
  after the line number.
  On Gtk, this meant resetting all the marker symbols and their
  foreground/background colors as well as the margin's colors themselves.
  This looks like a bug. It's not necessary on Scinterm, which apparently
  uses the default/linenumber styles by default.
  Perhaps we should try upgrading Scintilla?
* The folding state is considered not to be directly controlled by the
  language (just like the scroll position and zoom level). That's why
  we can directly control it by clicking on the margin column.
* F1 can be used to toggle all folds globally.
* The only support within the C core necessary for folding is to make
  sure that the current line is unfolded after every keypress.
* We might add custom folding commands to the language later on
  (e.g. F+, F-). In this case, the key macros will have to be changed
  of course.

* Using the same values as on Curses/scinterm resulted in too dark colors with
  terminal.tes. (solarized.tes actually defines all colors with its own RGB values,
  so the look has always been consistent between Curses and GTK.)
  This is because the values like 0xFF0000 for red are actually just placeholders in Scinterm,
  in turn translated internally to Curses colors, which are interpreted by terminal emulators
  with possibly various different color palettes.
* We therefore now use the exact RGB values as will be used by common terminal emulators
  like xterm and st.
  It does not guarantee that the colors will always match between Curses and GTK,
  but at least the GTK colors are now a bit brighter.

* The previous convention of !* ... *! are now true block comments,
  i.e. they are parsed faster, don't spam the goto table and allow
  embedding of exclamation marks - only "*!" terminates the comment.
* It is therefore now forbidden to have goto labels beginning with "*".
* Also support "!!" to introduce EOL comments (like C++'s //).
  This disallows empty labels, but they weren't useful anyway.
  This is the shortest way to begin a comment.
* All comment labels have been converted to true comments, to ensure
  that syntax highlighting works correctly.
  EOL comments are used for single line commented-out code, since it's
  easiest to uncomment - you don't have to jump to the line end.
  This is a pure convention / coding style.
  Other people might do it differently.
* It's of course still possible to abuse goto labels as comments
  as TECO did for ages.
* In lexing / syntax highlighting, labels and comments are highlighted differently.
* When syntax highlighting, a single "!" will first be highlighted as a label
  since it's not yet unambiguous. Once you type the second character (* or !),
  the first character is retroactively styled as a comment as well.

* NOTE: Selections are currently only used to highlight search results.
* The default selection colors were not always visible well with default settings (--no-profile)
  and they were not uniform across platforms.
  On Curses, the selection would be reversed, while on Gtk it had a lighter foreground color.
  They are now always reversed (black on white background).
  The default styles do not assume any color support - they use only black and white.
* Since these defaults cannot possibly work on every color scheme,
  color.selfore and color.selback has been added to color.tes.
  All existing color schemes have been updated to configure selections as reversed
  to the default colors.
  This especially fixes selection colors on Gtk.
* On solarized.tes, the caret style was already distinct from inversed default colors.
  On terminal.tes, the color of the caret is now bright white, so it stands out
  from the selection colors.
* In Curses, the caret color is currently __not__ applied to the command line where
  it is continued to be drawn reversed.
  The command line drawing code is considered deprecated and will eventually be replaced
  with a Scintilla minibuffer.
* In Gtk, we now apply the caret style to the commandline view as well.
* Fixed the comment color in solarized.light.

 * the RGB values of the 8 standard colors defined by color.tes
   were wrong (i.e. did not correspond to the normal 8 color codes
   defined by Scinterm but only the bright versions).
   Except for `color.black` which referred to terminal color 0.
 * now we define the 16 colors defined by Scinterm, allowing color
   schemes to explicitly use bright color versions without using the
   bold attribute. On 8 color terminals, the bold attribute might
   still be the only way to get a bright color.
 * terminal.tes: Use bright default color instead of relying on bold
   to get bright color versions. This is especially important for
   comments which where relied on bold black to be rendered grey.
   This did not work by default on terminals supporting bold fonts
   (e.g. OS X Terminal) or GTK+. The scheme now works on more
   terminals out of the box and on GTK+ and is thus a good default
   color scheme.
 * Color schemes will now also define the default style, the line number
   style and caret foreground/background.
   `color.calltip` is now also defined for STYLE_CALLTIP and can later
   be used to style SciTECO's custom popup widget.