graphics/piddle update

[Dominic Mitchell]

I'm attempting to update graphics/piddle to the latest version.
I think I need to use PORTEPOCH because the version number has gone from
1.0b1 to 1.0.15.  At the same time, I think it would be a good idea to
use PYTHON_PKGNAMEPREFIX.

So the package would move from being "piddle-1.0b1" to
"py24-piddle-1.0.15,1".  Is that reasonable?  Or do I not require the
PORTEPOCH because the name is changing?

Thanks,
-Dom