programmable terminal color redefinition and theming SciTECO curses UI based on Scintilla styles

 * The first 16 colors of the terminal palette can be redefined
   using the 3EJ property - with all restrictions that ncurses
   and UNIX terminals impose on us.
   It is still important to be able to redefine the palette for
   some color schemes like Solarized since it may be difficult
   for users to set up the terminal emulator's palette manually.
   Also when using PDCurses, setting the palette is port-specific
   or only possible using init_color(). In order to allow color
   redefinitions across all curses ports it makes sense if SciTECO
   gives access to the color initialization of curses even if it can
   guarantee very little about its semantics in general.
 * 3EJ is completely ignored for GTK+
 * use the STYLE_DEFAULT of the current document to style the message line.
   Fg and bg colors are reversed to guarantee a good contrast to the
   Scintilla view.
   Errors are still hardcoded to a red background, warnings to yellow
   and info messages to green.
   This allows color-scheming more of SciTECO given that the
   red, yellow and green terminal colors are not changed fundamentally
   in the terminal's palette.
 * info line is now also styled using STYLE_DEFAULT (reverse colors).
   The Q-Register and buffer names are now written out using format_str()
   which means that control characters are written out in REVERSE just
   like in the command line.
   String::canonicalize_ctl() is still used to canonicalize window
   titles.
 * Command line is now modelled as a curses Pad and "blitted" to the
   command line window. This allowed simplification of the command line
   drawing code and introduction of format_str().
   The command line is now styled according to STYLE_DEFAULT (original
   fg and bg colors).
   The rubbed-out part of the command line can now longer be shown in
   bold black - or even bold light black - since that is not visible in
   all color themes. Instead it is now only shown in bold.
   Command line theming problems will be gone once we use a Scintilla
   view for the command line.
 * The popup widget is now styled according to STYLE_CALLTIP.
 * This means that all relevant parts of SciTECO's user interface
   can now be themed. This allows the creation of themes that redefine
   the terminal palette radically (e.g. Solarized) and the creation of
   "bright" themes (e.g. Solarized/bright).
 * theming of the non-scintilla-view parts of SciTECO is currently
   unsupported on GTK+. The reason is that both the popup widget
   and command line widgets have to be rewritten completely in GTK+
   and are work in progress, so adapting the current code would be
   a waste of time.
 * Added a manual section about the UI and theming.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/interface.h b/src/interface.h
index 6c847f4..e93ebe3 100644
--- a/src/interface.h
+++ b/src/interface.h
@@ -193,13 +193,15 @@ public:
 		return NULL;
 	}
 
-	/* expected to initialize Scintilla */
 	inline void
 	main(int &argc, char **&argv)
 	{
 		impl().main_impl(argc, argv);
 	}
 
+	/* makes sense only on Curses */
+	inline void init_color(guint color, guint32 rgb) {}
+
 	enum MessageType {
 		MSG_USER,
 		MSG_INFO,