Add mention of mopidy-convert-config
docs: Fix typo and level of header
docs: Use 'config' more consistently
docs: Remove mixers' module docs
docs: Add section on extension config and disabling
docs: Add glossary (fixes #430)
docs: Add how to get good sound on raspis (fixes: #299)
docs: Review Raspi sound quality howto
docs: Fix typo
docs: Fix dist-upgrade command (fixes #470)
(cherry picked from commit 31ef29e1216a856a3ce72551516ef61ea4af7701)
docs: Fix link to rpi-update
config: Formatting
config: Raise ValueError if Path is asked to serialize unicode

If we accept unicode and try to encode using sys.getfilesystemencoding() then
it may work most of the time, but will fail if we get non-ASCII chars in the
unicode string and the file system encoding is e.g. ANSI-something because the
locale is C. Thus, I figure it is better to always fail if we try to serialize
Path from unicode strings. Paths should be maintained as bytes all the time.
tests: Use utf-8 when encoding our test data paths to bytes
Allow pyspotify 1.9 and higher, including 1.11
Bump version number to 0.14.2
docs: Update changelog for 0.14.2
Release v0.14.2
Merge remote-tracking branch 'mopidy/master'
Merge branch 'master' into develop

Conflicts:
	docs/changelog.rst