save aadt in its own doc too

I forgot to save aadt in the couch_file process, and I was going to
hack it into couch_file, but then I decided otherwise.  Although
couchdb is all about denormalizing data, it doesn't make
sense to me to stuff a yearly sum into each cell

On the other hand, it does make sense to stuff the fraction.  But
I am not sure that is the way to go yet.  So in the interim, just
save hourly stuff in the hourly docs, and then mix with the yearly
stuff from the aadt docs

new file:   lib/couch_aadt.js
modified:   lib/couch_file.js
new file:   test/test_couch_aadt.js