[Twisted-Python] pb size limitation

[Brian Warner]

> > If you really do want to change the size limit for banana, you can do it
> > per-process (patches to properly parameterize this accepted) by changing
> > banana.SIZE_LIMIT.
> 
> Just curious, but is this settable with cBanana?

No, not really. We could make it a modifiable attribute, but I'd rather not
for the same reasons described before, plus the fact that sending more than a
few tens of kb in a single banana token is just going to get queued anyway,
as the socket buffers aren't usually very big.

Banana is meant for sensibly-sized pieces of data. Bulk file transfer should
be built on top of it.

 -Brian