* Restructure the classes to allow the introduction of Virtual Geometry (aka Tracking Surfaces)
* Allow for mutable materials in GeoLogVol.  Useful for gases and other stuff which can be piped in.

* Typo fix in the deduplication of full physical volumes
* Introduce `cloneVolume()` helper function
* Augment the early testing capability against Athena
* Disable by default deduplication mechanisms
* Deduplication steering flags moved into the processor registries
* Disabled cloning in resize of GeoATLAS by default
* `gmcat`: don't fail if the local GeoModelData git repository is not accessible

Creating of 5.2.X changes w.r.t 5.1
```
* Typo fix in the deduplication of full physical volumes
* Introduce cloneVolume helper function
* Augment the early testing capability against athena
* Disable by default deduplication mechanisms
```

Changes w.r.t. 5.1

- Bug fixes when GeoPhysVols with Full physical volumes as children are deduplicated
- Add functionallity to the GeoDeDuplicator to switch off deduplication of Shapes, LogVols, GeoTransforms
- Disable deduplication by default
- Augment early testing in Athena  to test simulation & MC simulation in the CI
- Memory leak fix in GeoElement
- Introduce clone helper function to GeoHelpers.

* GeoModelFunctionSnippets renamed to GeoModelHelpers.
* De-duplication code is in place, which can be used to share Shapes and Physical Volumes automatically.
* The material manager code is simplified and put in one place.
* Several cosmetic changes in the gmcat utility

* GeoModelFunctionSnippets renamed to GeoModelHelpers.
* De-duplication code is in place, which can be used to share Shapes and Physical Volumes automatically.
* The material manager code is simplified and put in one place.

* Fix move semantics avoiding leakage of reference counts once the absolute position of a volume is requested.

* Remove explicit from default constructor
* Add possiblitiy to construct IntrusivePtrs from Child classes.

Patched `GeoIntrusivePtr` by adding template specification of the comparison operator. This was necessary for fixing C++ 20 compiler warnings

This release  introduces the IntrusivePtr, which automatically increases/decreases  the reference count of pointed-to objects with pointer construction/destruction. 

Other changes:  default transform for Alignable transforms are now persistified in  GeoModelWrite, rather that aligned positions. 
Convenience functions for input/output are added.

The main changes affect GeoModelKernel and GeoModelIO:

* For the GeoVGeometryPlugins, the interface was changed.  Now written to the GeoVPhysVol interface, allowing either full or ordinary phy vols to be created from a plugin.
* Bug fix in GeoModelWrite (all phys vols stored and phys vols) and greater generality in GeoModelRead (either fullphysvols or physvols are resolved at the top of the geometry tree)
* Update GeoModelExamples, GeoModelTools, and GeoModelVisualization to new interfaces

just a dummy tag to test the CI

New functionality to reliable compute the mass of all volumes, including complicated ones like Boolean volumes.

This tag is for the "CHEP" release, which aims to fix little problems with fullSimLight/FSL ahead of the CHEP conference May 8-12 in Norfolk Va.

* Configuration of HEPMC3 & Pythia in make is rationalized.
* Pythia/HEPMC3 options grayed out if not available.
* Crash of fsl on Ventura platforms fixed.
* Unphysical values of materials in KitchenSinkPlugin corrected
* New functionality in GeoModelXML

From 4.4.2:

* Introduce mechanism in GeoModelXML to pass readout geometry tables through to sqlite
* Also, create a FullPhysVol table and an AlignableTransform table in GeoModelXML, pass through to sqlite
* Fix a bug in GeoModelWrite leading to spurious (Full)PhysVols upon restore.
* Inhibit vectorization where it is unsafe (Scott's fix)

From 4.4.3:
* fix a compilation problem with FSL on somewhat older distributions of Qt.

* Introduce mechanism in GeoModelXML to pass readout geometry tables through to sqlite
* Also, create a FullPhysVol table and an AlignableTransform table in GeoModelXML, pass through to sqlite
* Fix a bug in GeoModelWrite leading to spurious (Full)PhysVols upon restore.
* Inhibit vectorization where it is unsafe (Scott's fix)

This is a patch tag to fix the FullSimLight and FSL single-builds. It also lets users disable HepMC3 support.

In particular, this patch tag:

* fixes the build of the FullSimLight and FSL sub-packages when built as top-tree packages on top of the other GeoModel packages. This is needed to successfully build the GeoModel distribution kits, such as the Homebrew 'bottles' for macOS.
* introduces a new CMake option to FullSimLight, to let users disable the dependency on the HepMC3 exchange data format, if not needed or not installed. The use of the new flag also disables the FSL GUI element related to the HepMC3 input.

This tag rolls up multiple developments over the summer.  These mostly involve fullSimLight and its graphical user interface, FSL, which has now reached a high level of maturity.  They also involve gmex, which has been enhanced with additional features allowing the visual examination of fullSimLight output. 

FullSimLight/FSL updates:

* All of the ATLAS-specific functionality hardwired into fullSimLight has been moved into plugins.
* The ATLAS-specific plugins (mag field, LarCustomSolid) have been moved to a submodule (geomodelatlas/ATLASExtensions)
* FullSimLight/FSL now takes HepMC3 input
* FullSimLight/FSL now inputs physics list plugins.
* FSL interface streamlined, selections are now displayed in the interface.
* The possibility to change fullSimLight behaviour by editing macros through the gui, judged too confusing, is removed.
* Several "dummy" plugins, serving as examples, are provided.
* Plugins to write out hits and/or tracks are provided. Output in HDF5 format. 

gmex:

* visualization of G4 hits and G4 tracks provided.

Removed printouts from GeoModelKernel/GeoVolumeTagCatalog.h