Update qclient, update release notes

CHANGELOG.md

 # Changelog
 All notable changes to this project will be documented in this file.
 
+### Unreleased
+- Better memory management and recycling, putting less pressure on the global
+memory allocator.
+- Addition of pub/sub support, commands implemented: ``PUBLISH``, ``SUBSCRIBE``,
+  ``PSUBSCRIBE``, ``UNSUBSCRIBE``, ``PUNSUBSCRIBE``
+- Addition of ``--steal-state-machine`` flag to ``quarkdb-create`` to make
+  transition from bulkload mode to raft easier.
+
 ## 0.3.5 (2018-11-28)
 - Updated rocksdb dependency to v5.17.2.
 - Improved output of backup command ``raft-checkpoint``. The generated directory

qclient @ 868e222d

-Subproject commit 26cb9ff78b7945c55860dc10a0173288447ebbf8
+Subproject commit 868e222d8a55454eee3ebda1add2b57bc6637dd4