fast fix: bug appeared in PropView of "resize_object_add" after adding default property
editor: "Save" save only JSON format
generator: don't add 'json' extension to filename
generator: put JSON_Version tag into JSON and parse it back
parser/generator: remove "@egui" marker, now json must be in separate file
egui_layout: put json desc into separate file. update CMakeLists.txt
cmake update file names
clean up
egui: -p option not supported anymore

  - egui_layout generation CMake fixed
egui options: forbid usage of -e and --json at the same time
generator: don't generate "Desc - type" section
egui layout: remove "Desc" and "type" sections
example: update json; rename/remove files
gui builder: fileselector default path is taken from context
Gui Builder: using export_filename/path when generating source code
Generator: refactoring

  we separately generate: JSON, C, CPP; so make separate modes for them
Gui Builder: adding Radio widget

   - adding group_add func to database
egui logic: refactor fileselector open mode, prepare for EXPORT mode
Adding radio buttons to fileselector

 - add to egui_layout JSON
 - add to egui_layout_c.src
Gui Builder: add Export mode to Project menu