Log Message:
Import libunique-3.0.2 as wip/libunique3.

Unique is a library for writing single instance application. If
you launch a single instance application twice, the second instance
will either just quit or will send a message to the running instance.

Unique makes it easy to write this kind of applications, by providing
a base class, taking care of all the IPC machinery needed to send
messages to a running instance, and also handling the startup
notification side.

Unique aims to replace the BaconMessageConnection code that has
been copied by many projects and the code using Bonobo and D-Bus.