Rethrow an exception like in C++?

[Rob T]

One more thing, we finally got __FUNCTION__ (and more) added to 
MASTER so that's another missing item that was sorely missed. Now 
we can easily log what functions are catching and throwing 
exceptions, and more.

The big question is if Throwable will be expanded to 
automatically capture the function signature (as it does with 
line and file)? I hope there are no major concerns over legacy 
code breakage and it gets added in.

--rt