Fluid: restructuring and rejuvenation of the source code.

* Add classes for application and project
* Removed all globals from Fluid.h
* Extracting args and project history into their own classes
* Moving globals into Application class
* Initialize values inside headers for some classes.
* Undo functionality wrapped in a class inside Project.
* File reader and writer are now linked to a project.
* Avoid global project access
* Nodes (former Types) will be managed by a new Tree class.
* Removed static members (hidden globals) form Node/Fl_Type.
* Adding Tree iterator.
* Use nullptr instead of 0, NULL, or 0L
* Renamed Fl_..._Type to ..._Node, FL_OVERRIDE -> override
* Renaming ..._type to ...::prototype
* Splitting Widget Panel into multiple files.
* Moved callback code into widget panel file.
* Cleaning up Fluid_Image -> Image_asset
* Moving Fd_Snap_Action into new namespace fld::app::Snap_Action etc.
* Moved mergeback into proj folder.
* `enum ID` is now `enum class Type`.

1 files changed, 0 insertions, 37 deletions

diff --git a/fluid/app/undo.h b/fluid/app/undo.h
deleted file mode 100644
index e8ffab891..000000000
--- a/fluid/app/undo.h
+++ /dev/null
@@ -1,37 +0,0 @@
-//
-// FLUID undo definitions for the Fast Light Tool Kit (FLTK).
-//
-// Copyright 1998-2025 by Bill Spitzak and others.
-//
-// This library is free software. Distribution and use rights are outlined in
-// the file "COPYING" which should have been included with this file.  If this
-// file is missing or damaged, see the license at:
-//
-//     https://www.fltk.org/COPYING.php
-//
-// Please see the following page on how to report bugs and issues:
-//
-//     https://www.fltk.org/bugs.php
-//
-
-#ifndef undo_h
-#define undo_h
-
-class Fl_Widget;
-
-#define kUndoWindowResize 1
-
-extern int undo_current;                // Current undo level in buffer
-extern int undo_last;                   // Last undo level in buffer
-extern int undo_save;                   // Last undo level that was saved
-extern int undo_once_type;              // Suspend further undos of the same type
-
-void redo_cb(Fl_Widget *, void *);      // Redo menu callback
-void undo_cb(Fl_Widget *, void *);      // Undo menu callback
-void undo_checkpoint();                 // Save current file to undo buffer
-int undo_checkpoint_once(int type);     // Save undo buffer once until a different checkpoint type is called
-void undo_clear();                      // Clear undo buffer
-void undo_resume();                     // Resume undo checkpoints
-void undo_suspend();                    // Suspend undo checkpoints
-
-#endif // !undo_h