session: Split spotify.connect() into 3 Session methods: create, connect, reconnect
Remove the importation of connect() in __init__.py
Remove connect() from the mockmodule
Namespace correction in the session manager.
Make Session.create() follow the typical calling convention.
session: Fix argument handling in connect().
Session manager: actually connect when connect() is called.
tests: Add a test for Session.create().
manager: Attempt to reconnect if the user provides no username.
Create class spotify.Settings to store session settings.
jukebox: minor modifications for testing logout/login.
Merge remote-tracking branch 'mopidy/develop' into session-split-create-connect

Conflicts:
	src/session.c
settings: Add proxy settings.
jukebox: Don't crash when 0 playlists are found.
docs: Add the third bitrate value
session_manager: stop the main loop after being logged out (adds a new callback).
tests: fix session tests.
session: call the logged_out() callback if _manager_logged_out() is not defined.
session: rename (re)connect() -> (re)login()
Update documentation and changelog