Update release notes for 0.3.4

.gitignore

@@ -2,3 +2,5 @@ src/Version.hh
 packaging/quarkdb.spec
 _book/
 .vscode
+*.sublime-project
+*.sublime-workspace

CHANGELOG.md

 # Changelog
 All notable changes to this project will be documented in this file.
 
-## Unreleased
+## 0.3.4 (2018-10-09)
 - Updated rocksdb dependency to v5.15.10.
 - Added `TYPE` command.
 - A read-only MULTI immediatelly after a read-write MULTI could
   cause the cluster to crash.
+- Added command `LHSCAN` for scanning through a locality hash.
+- Added convenience command in recovery mode for performing forced membership updates.
+- It's now possible to issue one-off commands from the recovery tool, without setting up a server.
 
 ## 0.3.3 (2018-09-14)