Make WatchDog listen for compile errors

[Inventitech]

I just discovered that I often look at my tests as late as when the production change is per-se ready. Then I see the API to my production code has changed and realize I have to adopt my tests to make them compile.

Eclipse provides ad-hoc compile success information. We could try to listen for them to detect such development behavior similar to mine.

@azaidman
@gousiosg