Read options from a file

[erkia]

Currently the only way to pass options (including password) to librespot is via command line. This means that username and password show up in a process list, which makes my eyes bleed.

Simple feature such as reading options from a file is much appreciated.

[ashthespy]

Reading configuration files shouldn't be part of librespot as a core feature, but libespotd

[michaelherger]

If you define a cache folder to be used, librespot would write out credentials to a credentials.json file.