Lib3mf

- Support for the Secure Content Extension of the 3MF format https://github.com/3MFConsortium/spec_securecontent/blob/master/3MF%20Secure%20Content.md. A minimal example for reading and writing is in the binary SDK (under Examples/Cpp/Source/SecureCube.cpp), as well as here in the tests: Tests/CPP_Bindings/Source/EncryptionMethods.cpp.
Note that lib3mf does not provide the cryptographic algorithms specified in the Secure Content extension. The tests of lib3mf make use of https://www.libressl.org/.
- Write-support for the Production Extension with non-root models https://github.com/3MFConsortium/spec_production/blob/master/3MF%20Production%20Extension.md.
- Support for version 1.1.0 of the beamlattice extension

This beta pre-release for version 2.1.0 of lib3mf has been deprecated.

This alpha pre-release for version 2.1.0 of lib3mf has been deprecated.

Version 2.0.1 resolves a security issue (double free / use after free) in the usage of of libzip (https://talosintelligence.com/vulnerability_reports/TALOS-2020-1226).

**Version 2 is a major overhaul of lib3mf. The most important changes compared to versions 1.\* are:**

- **autogenerated language bindings** for C++, C, Python, Pascal, C, Golang and NodeJS have been added
(the defunct COM interface has thus been removed)
- the handling of properties has been reworked
- **multiproperties** and **compositematerials** are now supported (finally!)
- **metadatagroups** are now supported
- **object-level properties** are now supported
- the documentation of lib3mf is now treated as source-code. It is automatically built and hosted on
https://lib3mf.readthedocs.org/ (WIP)
- the Windows binary lib3mf.dll is now digitally signed
- deprecated/non-implemented functionality has been removed
- performance has been drastically increased when dealing with high numbers of (small) resources and build items
- properties of mesh-objects can be cleared
- fixed beamlattice representation mesh
- encode XML escape characters in the text of nodes
- consistently use `MAX_MESH_*COUNT` and similar
- UTF-16 (`wchar`)-version of all API-calls with `strings` have been removed: only option is now UTF-8
- numerous minor issues have been fixed or improved

This beta pre-release for version 2 of lib3mf has been deprecated.