Add debug logging

[MarkusG]

This addresses #113.

• Add a log domain in meson.build
• Add logging for the following:
  • Playerctl version at startup
  • Found players
  • Command execution
  • Warning for mpris;trackid not being a D-Bus object reference
  • Player properties changed events
  • Warning when playback status is not set on track change
  • Capitalize warning for unknown playback state
  • Player seeked event
  • Warning for Spotify not using the D-Bus property cache
  • Warning for D-Bus socket address when attempting to list player names on a bus
  • Getting bus names for player names, and which method is being used
  • Warning for bus address being set incorrectly in player init
  • Initializing cache for player

[acrisci]

Cool looks like a pretty good start.

You have some whitespace issues that need to be fixed.

Works with this:

G_MESSAGES_DEBUG=playerctl ./build/playerctl/playerctl

[MarkusG]

Whitespace issues corrected in df9a465

[acrisci]

👍