basic EXTM3U playlist support
EXTM3U playlist saving
add translator tests for EXTM3U files
add translator tests for EXTM3U files
fix writing of runtime to EXTM3U
add playlists test for writing EXTM3U files
fix flake8 error E302
Merge branch 'feature/extm3u' of https://github.com/tkem/mopidy into develop

Conflicts:
	mopidy/backends/local/translator.py
docs: Add extend M3U to changelog