Watch delivers current state for resourceVersion=0

Allows clients to get the current state without having to execute
a get followed by a watch.  Makes integration with action loops
much cleaner.

Split from #846
It occurs to me now that TransformFunc and my own FilterFunc are actually better applied as a separate, layered watch.

e.g., in the watch package, ```func Filter(w Interface, f FilterFunc) Interface``` and ```func Transform(w Interface, f TransformFunc) Interface```. Or they could even be combined, with FilterFunc returning the new object and whether to send it.

I can do that in another PR if you don't want to do it here.