* interactive layout alignment rewritten
* interface for new alignment rules
* new alignment dialog box
* user defined layout rules added
* layout rules can be stored in projects, settings, and external files
* Valgrind verification
Removing all globals in file writer (#653 )
Fix some static analyser complaints
Valgrind: handle width==0 in GfxDrivers on Wayland and X11
Don't use `Fl_Input_::static_value`, it accesses previous
buffer that may be deleted
Project file write encapsulated, removing globals
Encapsulating project file reader, removing states in glbals
Project i/o increased source code readability
Fluid would add pasted widgets as the last child of the
current group, even if they were cut at the beginning
of the group. This patch adds a 'startegy' to adding
widgets to allow merging closer to the 'current' widget.
Also added d'n'd for the widget bin and some other
UI improvements.
STR 3442: some preparation, variable renaming
STR 3442: unifying functions to add widgets.
Adding widgets interactively is merged into one function,
making undo/redo work as expected and removing
unexpected differences between adding by menu or bin.
STR 3442: adding drag'n'drop for windows from bin.
Just drag the window symbol out of the tree and drop it anywhere
on the desktop.
Visual representation of dragged Window.
STR 3442: insert individual nodes after 'current'
STR 3442: adding new widget at expected positions.
The widget bin can finally do drag'n'drop.
Widgets appear in the tree close to the last selection.
Duplicating now ads right below.
Cut and paste inserts after last selection.
Fluid: replaced #define with strict enum type.
tl;dr : making Fluid maintainable, no changes in code execution and logic.
This is a pretty extensive restructuring of the Fluid source tree.
It was neccessary because source and header files were getting
much too big to handle. Many source files had no header, and many
headers declared functions that were in diffrent source files.
Reorganized much of the include statements.
Added comments to some of the files.
Added Doxygen configuration file for standalone Fluid docs.
Tested everything by rebuilding Fluid .fl designs with the resorted
version of Fluid.
