Implement YYSpine v3 format

[nkrapivin]

Fixes Death's Gambit.

Description

Fixes issue #1095 and adds a bit more comments to the Spine classes.

Renames PNGBlob property of the Spine texture entry class to TexBlob because the Spine data may no longer be a PNG texture, can also be a GameMaker QOI format (not bz2 compressed as for now?).

Caveats

Any scripts or code that used the PNGBlob property of the Spine texture entry class, or thought that Spine textures are de-facto PNG files will not work properly.

Notes

I don't have Death's Gambit win in possession nor do I own Spine legally so I can't really test this.

[nkrapivin]

The first commit will probably fail to compile cuz I didn't change the editor xaml cs, second one should be OK

[github-actions]

Download the artifacts for this pull request here:

GUI:

• GUI-windows-latest-isBundled-false-isSingleFile-false
• GUI-windows-latest-isBundled-false-isSingleFile-true

CLI:

• CLI-macOS-latest-isBundled-false
• CLI-ubuntu-latest-isBundled-false
• CLI-windows-latest-isBundled-false

[Miepee]

Might wanna add to the PR description that PNGBlob got renamed to TexBlob as that is a breaking change as well.

[nkrapivin]

Done. I still suggest using the term GameMaker QOI and not QOI because YoYoGames's implementation of QOI differs from the original spec on GitHub.

[nkrapivin]

🤨