eyre: forego <atom> in favor of (scow %aura atom)
eyre: forego <atom> in favor of (scow %aura atom)

Pretty-printing is expensive, yet we do it whenever we construct the cookie
string, at least once (but usually twice) per authenticated request.

Here we call out the the specific to-tape functions we need, instead of relying
on the pretty-printer for converting... tapes to tapes, among other things.  
The primary gains come from the cookie-related instances, we update the others
mostly for good style.

For the "receive request and immediately send response" case, that is processed
synchronously within eyre (ie, client sends channel ack), speeds thing up by
roughly 55%.
ngzax/urbit,urbit/urbit,urbit/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit