Bug fixes from h2o-dev

FetchAck priority level (so an RPC response containing a new type can
fetch the type & id from the leader even if its the leader sending the
RPC response).
AutoBuffer.close takes no args & is idempotent.
H2O priority queues, worker threads do not surf other low-priority
worker thread queues.
Merge branch 'master' of github.com:0xdata/h2o
Merge branch 'master' into cliffc-bugs

Conflicts:
	src/main/java/water/util/ChunkSummary.java
Merge branch 'master' into cliffc-bugs
Missing FETCH_ACK priority in fetch calls
RPC local cleanup

Move all completions into subroutine.
Missing fetch-ack priority.
No need for local-vs-remote block/waiting; local callbacks complete the
RPC as normal, so the normal block/wait wakes up fine.
Merge branch 'master' of github.com:0xdata/h2o

Conflicts:
	src/main/java/water/util/ChunkSummary.java
Merge branch 'master' into cliffc-bugs