Patches to review

[Yuriy Skalko]

> All the patches are fine. I have only one remark concerning Counters::copy. I do not understand why this is a Counters method _and_ it receives two Counters instances as parameters. This looks like a badly specified method.
> 
> 
> OTOH, it looks like it is not used. What about removing it ?
> 
> JMarc

Committed all.

I'm doing constification in semi-automatic mode and don't put enough 
attention to methods purpose. Really this method should be removed.

Yuriy