use lists instead of arrays

in Scala it is much easier to use lists instead of arrays. They are
translated the same in js by js-scala, thus why not use them?
fix type of reduce function

the type of the list of keys was inverted. The key comes first, and then
the original document id.
add support for unified documentation

Code from akka borrowed to generate a unified documentation site from
all sub-projects
add a method to retrieve only one UUID

this basically just extract the first (and only) element of the UUIDs
list, but makes the client code look better
code and comment cleanup
add support for couch client in tests