Use function for sending krpc responses, and add spew parameter.

Use function for sending krpc responses, and add spew parameter.

Sending a response in the krpc module now calls a function.

There is a new 'SPEW' config variable that causes the krpc
module to spew out all sent and received packet data
(previously called noisy).

Also changed all the tests to use failUnlessEqual instead
of assertEqual, and all assert() commands no longer use
brackets.

Updated some of the downloading tests for the new file sizes
on camrdale.org (need a better solution here).