Unable to compile Tracks (GTD) plugin

I have been unable to compile Sebastian Ruml's plugin [1] for Tracks [2], and since it seems unmaintained, I'm unsure as to whether it's supposed to work with recent versions of GNOME Do. I'm not very familiar with gmcs, so the error may well be on my part.

The error output is:

$ gmcs -target:library -r:System Tracks.cs
warning CS8029: Compatibility: Use -r:LIBRARY instead of -r library
Tracks.cs(22,7): error CS0246: The type or namespace name `GConf' could not be found. Are you missing a using directive or an assembly reference?
Tracks.cs(24,10): error CS0234: The type or namespace name `Universe' does not exist in the namespace `Do'. Are you missing an assembly reference?
Tracks.cs(31,36): error CS0246: The type or namespace name `IItem' could not be found. Are you missing a using directive or an assembly reference?
Tracks.cs(22,7): error CS0246: The type or namespace name `GConf' could not be found. Are you missing a using directive or an assembly reference?
Tracks.cs(24,10): error CS0234: The type or namespace name `Universe' does not exist in the namespace `Do'. Are you missing an assembly reference?
Compilation failed: 5 error(s), 1 warnings

I'd appreciate some help from people who may have been able to get it to work with a recent version, and if changes are needed, wouldn't mind learning the steps that need to be taken to get the code into shape and possibly get it into the community plugins repository.

[1] https://code.launchpad.net/~sebastian-ruml/do/TracksPlugin
[2] http://getontracks.org

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Update: I've contacted Sebastian about this. It seems the plugin was pre-Mono.Addins, and needs to be adapted to it. We'll see what we can do.