Fix Circle CI and Codecov badges

[nickserv]

The project seems to have been removed from both services, they might as well be cleaned up and removed from the readme and source files.

[nickserv]

Hmm I failed to notice that Circle CI and Codecov are still processing pull requests here, maybe the badges just need to be changed?

[tleunen]

The project is not really maintained anymore so I guess we could easily remove them and I can remove the integrations too.