PolePosition

Garbage Collector should be invoked before each lap, in order to reduce the
noise of objects from the previous lap being collected in another lap.

I placed an invokation to System.gc(); just before watch.start() on line
144 of Circuit class.

Though GC cannot be forced, this suggest the VM to do its best effort on
collecting garbage. I think this invocation is a good idea because othewise
I could (in theory) penalize some database because several objects were
created for another database.

One could also argue that GC should be requested between the watch calls.