added simple reducer

simple reducer doesn't actually reduce...it just collects the output
from the couch_cacher type call and makes an array of the results,
with a header value and all that.

Contrast with the regular reducer, that actually sums up values by
freeway/timeperiod.

simple reduce also makes no attempt to compute vmt, etc.  It just
copies the records, and returns them.

Also a test

also messed up the API.  now using index.js