Updates to latest librespot, bringing along some larger changes under the hood.

Maintenance

Display error when command can not be parsed (#161)
Add rounding to volume percentage display (#493)
Log warning instead of panicking on invalid color (#498)
Update to librespot 0.2.0
- As part of this, a lot of the Future implementations were migrated to async/.await and cleaned up
Flip play/pause indicators (#511)

Features