Fits extension

[LuckyEddie47]

This extension adds .fits file compatibility to Nemo.

.fits are the default image format used for astronomical imaging. It is an open spec that was originally created by Nasa - https://heasarc.gsfc.nasa.gov/docs/heasarc/fits_overview.html

The extension uses the cfitsio which is standard within Debian.
A thumbnailer is provided along with Image information extracted from the .fits header.

Full disclosure - Having very little experience with GTK I used claude.ai to author this extension. I've tried to force it into following the style and standards of the rest of the extensions in the repository. I have black-box tested only. I haven't found any stability or performance issues. fits file compatibility seems to be good but this is almost guaranteed as AFAIK all astronomical image writing applications also use the standard cfitsio library.

I've left off any copyright info, I'm happy for you to do as you see fit (pun intended).

[LuckyEddie47]

Just made WIP as I've discovered something missing in the build config. Investigating now.

[LuckyEddie47]

Finished testing on three different systems including one Raspberry Pi. Think this is good to go now.

[LuckyEddie47]

Now supports colour (standard 3-axis) and optional auto-stretches the thumbnail. Many/most astronomical images require a non-linear stretch to reveal the content.

[mtwebster]

Hi, don't edit nemo-extensions.pot please, updating the makepot script is sufficient (we'll run that ourselves during pre-release).

Also please condense the changelog into a single 'Initial release' description.

Thanks

[leigh123linux]

Can you rebase this into a single commit.

[LuckyEddie47]

I think I've made those changes now (I'm not a git guru but it seems to have worked to me).

[leigh123linux]

I think I've made those changes now (I'm not a git guru but it seems to have worked to me).

Looks good, thanks.