Upgrade libgltf to 0.0.1

News in this version:
- Solve some limitations of walkthrough mode (fdo#81425)
- Multisampling (better rendering quality, mainly at the edges)
- Better error handling (no crash in case of invalid input file)

Reviewed-on: https://gerrit.libreoffice.org/11179
Reviewed-by: Zolnai Tamás <tamas.zolnai@collabora.com>
Tested-by: Zolnai Tamás <tamas.zolnai@collabora.com>

Conflicts:
	download.lst
	external/libgltf/UnpackedTarball_libgltf.mk
	external/libgltf/pathces/append_shader_version.patch
	external/libgltf/pathces/missing_include.patch
	vcl/source/opengl/OpenGLContext.cxx

Change-Id: I46fdf56b00476614487fbcc04178e43e33a01794
Reviewed-on: https://gerrit.libreoffice.org/11194
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Tested-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>