To use the RPi3 with bluetooth headphones:
Load the pavucontrol extension, start bluetooth as explained above and then start pulseaudio by opening pavucontrol.
In the bluetooth command interface, issue the following command:
[bluetooth]# connect 00:1B:66:00:31:88
Attempting to connect to 00:1B:66:00:31:88
[CHG] Device 00:1B:66:00:31:88 Connected: yes
[CHG] Device 00:1B:66:00:31:88 UUIDs: 0000110b-0000-1000-8000-00805f9b34fb
[CHG] Device 00:1B:66:00:31:88 UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 00:1B:66:00:31:88 UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 00:1B:66:00:31:88 ServicesResolved: yes
..this will set the bluetooth headphones as an a2dp sink and the bluetooth headphones will appear as an available output in pavucontrol.
You can play music to the headphones using the xmms-pulse extension (use <ctrl-p> to access the configuration menu and choose the pulseaudio output plugin). Note that you may need to use pavucontrol to switch the output stream from the 3.5mm jack to bluetooth.
Optionally the blueman extension can be used to pair and set the headphones as an audio sink.
The issue now is that the music pauses every few seconds for the RPi3 to catch up