Added support for LM Sensors

[koutheir]

This uses libsensors as a source of temperature values, avoiding many issues with the current hwmon driver class.

Closes #156.

[vmatare]

Wow, that was fast and it's also looking quite good to me. No technical remarks after a superficial review, but there are some naming and formatting details I'd like to change. Then the logical next step would be to support fan config via libsensors, as well.

Since I think it's easier if I just make the naming- and formatting-related changes myself I'll change this PR to be merged into a topic branch, and then we can continue from there. I don't want to merge it into the master right away because there are some purely bugfix-related (as in, simple bugs) pending there.

[vmatare]

Oh, could you please add the libsensors-dev dependency here so we can get the CI running on this?

[koutheir]

Done.

[vmatare]

Weird, now gitlab acts like there is no CI at all. I'll just go ahead and merge this and continue working on the lm-sensors branch. Is it OK if I make you a collaborator so you can push to it directly?

[koutheir]

That's okay. Thank you for the trust!

[williamdes]

For some reason someone wrote a blog post using chip: it's not supported by the current version in Debian (already the latest). So I hacked into the Debian package and built it for the last commit of this repo.

After installing my custom .deb file it seems to work on my Thinkpad P73.

  - chip: thinkpad-isa-0000
    ids: [ CPU, GPU, temp3, temp4, temp5, temp6, temp7, temp8 ]

Any idea when this will be released ?