sslot 0.3 release

[Lutger]

Dejan Lekic wrote:
> Lutger, my suggestion is to do what QT does - http://doc.trolltech.com/4.2/threads.html#signals-and-slots-across-threads
> 
> Kind regards
> 
> PS. I would like to see this in Phobos' signal/slot implementation.

Thank you for the link. It is still not clear to me what is necessary, 
the QT s/s mechanism is tightly integrated to the whole framework so not 
seems to be applicable.

What it comes down to looks like a lot of mutexes to me though. I am not 
so familiar with multi-threaded programming, perhaps you can help me 
with these questions:

Would it be preferable to have a thread safety as an option, and if so 
in what way? Versioning or seperate classes?

Do reads from (non-volatile) data need to be synchronized?