Merge remote-tracking branch 'remotes/origin/master' into develop

Conflicts:
	CMakeLists.txt
	ChangeLog.txt
	THANKS.txt
	appveyor.yml
	config.mk
	installer/mosquitto-cygwin.nsi
	installer/mosquitto.nsi
	lib/messages_mosq.c
	lib/messages_mosq.h
	lib/mosquitto.c
	lib/mosquitto.h
	lib/net_mosq.c
	lib/net_mosq.h
	lib/send_client_mosq.c
	lib/send_mosq.c
	lib/socks_mosq.c
	lib/will_mosq.c
	src/bridge.c
	src/conf.c
	src/context.c
	src/database.c
	src/loop.c
	src/mosquitto.c
	src/mosquitto_broker.h
	src/net.c
	src/read_handle.c
	src/read_handle_server.c
	src/subs.c