* Still to do:
* Properly handle effects (disable 3D effects) for layers
* Handle hot reloading properly
* Avoid duplicating the configuration of the custom object inside each object created from it. Instead, only store the modified values.
* Add a "Extract as a custom object ("prefab")" when selecting instances in a scene.
* Add a dialog to give choice between 2D or 3D object when creating one.
* Make sure "behavior shared data" are properly handled (physics, pathfinding...)
* Check if we need to give an expression to translate coordinates from the parent to the local custom object.
* Ensure a deleted custom object does not break the editor
Co-authored-by: Davy Hélard <davy.helard@gmail.com>
- Global or scene variables can be used with a unique action and condition.
- Object variables can be used with a unique action and condition.
- Variables need to be declared following the same logic as the new expression syntax.
- Local variable can be declared on events
- Extensions have their own variables
- Show a diagnostic report when a preview is launched and there are missing scene variables, object variables or behaviors.
- This is especially useful if external events are shared between several scenes.
* You can now simply write the name of the scene or global variable in an expression to use it: `1 + MyVariable` (instead of `1 + Variable(MyVariable)`).
* Objects can also have their variables accessed like this: `MyObject.MyVariable` (instead of `MyObject.Variable(MyVariable)`.
* This also works for properties inside functions of behaviors or custom objects. For example, you can write `Speed` instead of `Object.Behavior::PropertySpeed()`.
* This syntax will also handle all types of variables without the need to write ToString. For example, you can now write "Score: " + CoinsEarned instead of "Score: " + ToString(Variable(CoinsEarned)).
* This syntax will only work (and autocompletions will be shown) if you add the variable in the variables editor of the scene, the project or in the variables of the object. It's a good practice to always declare your variables here and give them a default value - do it to benefit from this new simplified syntax, which will make your formulas and expressions much more readable.
* When you rename a variable in an editor, it will now rename the variables everywhere in the events of the project. This makes it much easier to change the name of a variable if you find a better one. Note that this works for "rootæ variables, but not variables inside structures or arrays.
* The editor used to refactor every events that were used in the object layout even if they were associated to another layout which could result to errors.
* This allows [custom behaviors](http://wiki.compilgames.net/doku.php/gdevelop5/behaviors/events-based-behaviors), that you can create in your project or get from extensions, to require the presence of one or multiple other behaviors on an object.
* This is an advanced feature that is helpful to create behaviors that are based on other. For example, a behavior "Platformer enemy" using the "Platformer object" behavior and adding specific actions, conditions and logic to make an enemy chase the player.
* If you create a behavior and want to use this, just go to the properties of this behavior and add a new property. Choose the type "Required Behavior" for this property. You can then use this new behavior in the events of the behavior you just edited.
* To use a behavior based on another, you don't need to do anything special! Just add it to your object as usual: any missing behavior will be added to your object, so you can start using it immediately.
* Update all CMakeLists of extensions to use clang-format
* Run clang-format on all Extensions
* Update GDCore CMakeLists.txt to add clang-format
* Run clang-format on GDCore files
* Update GDJS and GDCpp CMakeLists.txt to add clang-format
* Run clang-format on GDCpp and GDJS files
