Fix release build on linux with gcc 12

Some errors in cgltf library.

Bump version to 0.11.0

Fix compilation on Windows

Fix compilation on Windows

Bump version to 0.10.6

Reintroduce layer bounding box widget

It had been removed by mistake in an older commit.

Gui: minor change

Support export png with no transparent background

The whole export code will need to be improved.  I don't think we should
store export option in the image structure!

Add a changelog file

To make it easier to prepare new releases in the future.

Use getopt instead of argp

This is more portable.