## Summary of Changes
Fix a usability issue with Visual Studio Code. There is now a new target
`CGALlab_compile_all_plugins` that compiles the executable `CGALlab` and
all the plugins.
That target, as seen in the vscode Make Project Outline, is placed just
below the `CGALlab` target.
If the executable `CGALlab_compile_all_plugins` is launched, it just
displays:
```
This executable is not intended to be run.
Please run the CGALlab executable instead.
```
## Release Management
* Affected package(s): Lab
## Summary of Changes
Switching from `std::pair<Property_map<T>, bool>` to `std::optional` in
`Property_container::get<T>`
Introducing `Pair_optional_adaptor` for backward compatibility which
extends `std::optional<T>` to interface of `std::pair`
using `Pair_optional_adaptor` for `Surface_mesh` and `Point_set_3`
## Release Management
* Affected package(s): Point_set_3, Surface_mesh, STL_Extension
Sebastien Loriot
Laurent Rineau
Sven Oesau
ange-clement
Jane Tournois