improve frontend of emacs, ckeditor, tinymce, nicedit, meta and env functions

Improves in emacs:
- use htmx to send content to the controller
- show txt and formatted_txt content in the second panel
- show two tabs if "tabs" winix parameter is used
- add an option to show either one or two panels
- correctly resize the editor window (F11) when two panels are shown

Improves in ckeditor:
- use htmx to send content to the controller
- do not check automatically for ckeditor update

Improves in tinymce/nicedit/meta/env:
- use htmx to send content to the controller

while here:
- change PascalCase to snake_case in meta/env controllers
- update CodeMirror editor to 5.65.16
- udpate Showdown (markdown to html converter) to 2.1.0

winixd/functions/ckeditor.h

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2011-2014, Tomasz Sowa
+ * Copyright (c) 2011-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -37,11 +37,8 @@
 
 #include "functionbase.h"
 
-namespace Winix
-{
 
-
-namespace Fun
+namespace Winix::Fun
 {
 
 
@@ -50,16 +47,15 @@ class Ckeditor : public FunctionBase
 public:
 
 	Ckeditor();
-	void init();
-	bool has_access();
-	void make_get();
-	void make_post();
+
+	void init() override;
+	bool has_access() override;
+	void make_get() override;
+	void make_post() override;
 
 };
 
 
 } // namespace
 
-} // namespace Winix
-
 #endif