Update CHANGELOG for 1.6.7 (#5683)

CHANGELOG.md

@@ -1,3 +1,31 @@
+## Parity [v1.6.7](https://github.com/paritytech/parity/releases/tag/v1.6.7) (2017-05-18)
+
+This release addresses:
+
+- potential usability issues with [import and recovery of existing accounts](https://blog.parity.io/restoring-blank-seed-phrase/).
+- canceling scheduled transactions via RPC or UI.
+- warp sync issues with the Kovan network.
+
+Full changelog:
+
+- Backporting to beta [#5657](https://github.com/paritytech/parity/pull/5657)
+  - Add CHANGELOG.md [#5513](https://github.com/paritytech/parity/pull/5513)
+  - Reorg into blocks before minimum history [#5558](https://github.com/paritytech/parity/pull/5558)
+  - Bump to v1.6.7
+- Cancel Transaction [#5656](https://github.com/paritytech/parity/pull/5656)
+  - option to disable persistent txqueue [#5544](https://github.com/paritytech/parity/pull/5544)
+  - Remove transaction RPC [#4949](https://github.com/paritytech/parity/pull/4949)
+  - Cancel tx JS [#4958](https://github.com/paritytech/parity/pull/4958)
+  - Updating documentation for RPCs [#5392](https://github.com/paritytech/parity/pull/5392)
+- Backport Recover button [#5654](https://github.com/paritytech/parity/pull/5654)
+  - Backport [#5645](https://github.com/paritytech/parity/pull/5645)
+- Add monotonic step to Kovan [#5630](https://github.com/paritytech/parity/pull/5630)
+  - Add monotonic transition to kovan [#5587](https://github.com/paritytech/parity/pull/5587)
+- Fix ethsign [#5600](https://github.com/paritytech/parity/pull/5600)
+- Registry backports [#5445](https://github.com/paritytech/parity/pull/5445)
+  - Fixes to the Registry dapp [#4984](https://github.com/paritytech/parity/pull/4984)
+  - Fix references to api outside of `parity.js` [#4981](https://github.com/paritytech/parity/pull/4981)
+
 ## Parity [v1.6.6](https://github.com/paritytech/parity/releases/tag/v1.6.6) (2017-04-11)
 
 This release brings warp sync support for kovan network.