Read correct frame indices from TNG

[ezavod]

Depends on chemfiles/tng#1.

Updates the external TNG library to read the correct number of frames in a trajectory. Additionally, store the time of a frame as property, if present.

Fixes #425.

[Luthaf]

The changes looks good. I don't know why emscripten is failing on CI, I'll look into it.

[Luthaf]

So I managed to update emscripten (sorry for the force push noise …) but it is now failing on MinGW. Seems that the root cause is that tng_io.c is being compiled as C++ instead of C. That's a change from tng_io I though I did not pull in for chemfiles, but we might need to check & change CMakeLists.txt in chemfiles/tng#1.

[ezavod]

Thanks for your immediate action. I'll revert !27 here and if it works I'll add these changes to chemfiles/tng#1.

Edit: MinGW seems to work now, but codecov is down :-(
It seems we are using an deprecated uploader.

"The /bash endpoint is currently unavailable due to a scheduled brownout. The brownout schedule and more information can be seen found at https://about.codecov.io/blog/codecov-uploader-deprecation-plan/. It is recommended to update this repository to use the binary uploader, instructions can be found at https://docs.codecov.com/docs/codecov-uploader. This endpoint will permanently cease to function on Feb. 1, 2022."

Edit 2: Turns out I had a lot of luck and hit a 15 min time slot perfectly during which codecov had scheduled brownouts for soon-to-be deprecated services. However, simply copy and pasting the new uploader does not work.

[Luthaf]

Ok, let's merge this and we'll see later how we can have similar code upstreamed!