Better documentation for first-time use

[jbriales]

Awesome tool! Thanks so much, unlocked me from controlling Spotify volume via i3 shortcuts.

I feel the README doesn't provide much hints into how to leverage this MPRIS interface though.

These are the quick notes I wrote for myself:

• spotpris2 -l and spotpris2 -l id:
  show available devices and their IDs
  E.g. 79150f27eb368b66940ed4b6e765b673d29f58bc

• spotpris2: Start MPRIS DBus
  After this, you can search for 'spotpris' in 'd-feet' -> 'Session Bus' list
  and get the Name for a device,
  e.g. 'org.mpris.MediaPlayer2.spotpris.device79150f27eb368b66940ed4b6e765b673d29f58bc'

• Check current volume value:
  dbus-send --print-reply --type=method_call --dest=org.mpris.MediaPlayer2.spotpris.device79150f27eb368b66940ed4b6e765b673d29f58bc /org/mpris/MediaPlayer2 org.freedesktop.DBus.Properties.Get string:org.mpris.MediaPlayer2.Player string:Volume

• Set volume:
  dbus-send --print-reply --session --dest=org.mpris.MediaPlayer2.spotpris.device79150f27eb368b66940ed4b6e765b673d29f58bc /org/mpris/MediaPlayer2 org.freedesktop.DBus.Properties.Set string:org.mpris.MediaPlayer2.Player string:Volume variant:double:0.5

[freundTech]

The command line options including -l are already documented in the README.

The rest is not specific to spotpris, but all mpris devices, which is why I didn't document them here. dbus-send is only one option to interact with mpris devices. I personally would recommend playerctl as an mpris client, as it's syntax is way easier than constructing the dbus calls yourself.

[jbriales]

Maybe adding some relevant links to get started with these? Or even just your comment above, would be useful for newcomers and I don't think most people who can benefit from this SpotPRIS2 wrapper will be experts on dbus-send or playerctl.