Add and test dseq/move! function.
(Selfishly) specify Clojure 1.6 in :hadoop-user context.
Make tuple sources `r/fold`-able via `map-combine`.
Tuple sources are mutable turtles, all the way down.
Allow `pg/input` to handle a vector of `:input` nodes.
Convey thread bindings in `map-combine` tasks.
Handle a few more built-in writable types.
Add and use toolbox identity task function.
WIP; Updating documentation for 0.6.0.