yabar-unstable: 2018-01-02 -> 2018-01-18

The following changes landed in master:

- Reset colors unconditionally (2f1ee69d4c75e210265dca732ff6c2ddd7f440f2)
- Document NixOS support (993f1b5a7bc2a41a353a104cff0763860c053c92)
- ya_int_song: improve configuration of playerctl properties (1f776cd5f1f4e89e6ebca3ca09feb7e09f79e79e)