This reverts commit a988fad9a0.
As discussed in #57725 and clarified in #57788, `SNAME` is not meant to be used
everywhere but only in critical code paths. For theme methods specifically, it
was by design that only getters use `SNAME` and not setters.
- Allow OptionButton selection to be set to -1 to signify no selection, both via API and in the editor.
- Reset OptionButton selection to -1 when the selected item has been removed.
- Fully convert PopupMenu to a zero-based ID system, which improves an inconsistency in generated IDs when making new items in the editor.
* `_gui_input`, `_input`, `_unhandled_input` and `_unhandled_key_input` are now regular C++ virutal functions.
* Everything else converted to GDVIRTUAL
* BIND_VMETHOD is gone, always use the new syntax from now on.
Creating `_gui_input` method and using the binder to register events will no longer work, simply override the virtual function now.
Having a property which has the same name as its class leads to confusing
situations (e.g. `BaseButton` has a `shortcut` property of type `Shortcut`
which has a `shortcut` property of type `InputEvent`).
Also renames `is_event` to `matches_event`, and `is_valid` to `has_valid_event`
to better reflect what the methods check.
The internal processing code only works for OS windows, since it takes
the mouse position relative to the window and not the viewport. Now we
make sure it's not called in single-window mode.
* Added a new macro SNAME() that constructs and caches a local stringname.
* Subsequent usages use the cached version.
* Since these use a global static variable, a second refcounter of static usages need to be kept for cleanup time.
* Replaced all theme usages by this new macro.
* Replace all signal emission usages by this new macro.
* Replace all call_deferred usages by this new macro.
This is part of ongoing work to optimize GUI and the editor.
