Update mimetypes icons

[Bastián Díaz]

Hello everyone,

Finally, I was able to refresh the icons for mime types supported in PSPP. My main goal was to address the proper display of each icon with its corresponding canvas size (avoid blur) and I think I have succeeded. (I get any feedback for improvement).

I also added an image to ZSAV files under the same criteria. (I have not modified the file Smake)

Regards

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Bastián Díaz