Export extra connection methods.

In order to talk to PulseAudio, I need to connect directly to `"unix:path=/run/user/1000/pulse/dbus-socket"` (the actual socket path being retrieved from the PulseAudio discovery service via the session bus.) This is why I've found it necessary to export `connectTo` (formerly `connectSessionAt`) as well as its buddies `connectOver` and `connectUnix`.