registry dapp: cleanup, support reverse entries (#3933)

* style fixes ✨

* registry dapp: show reverse events

* registry dapp: actions & reducers for isTestnet

* registry dapp: make Hash & Address components

* registry dapp: code style ✨

* registry dapp: bugfixes 🐛

* registry dapp: postTx helper

* registry dapp: refactor reducers

* registry dapp: use react-redux

* registry dapp: actions & reducers for reverse lookup

* registry dapp: reverse lookup component

* registry dapp: connect Address to redux

* registry dapp: de-DRY recordTypeSelect

In preparation for the next commit.

* registry dapp: support reverse lookup

* registry dapp: render reverse events

* registry dapp: show tx sender, add key prop

* registry dapp: link accounts to etherscan as well

* registry dapp: address style grumbles 💄

* registry dapp: address style grumbles 💄

js/src/dapps/registry/util/etherscan-url.js

@@ -0,0 +1,26 @@
+// Copyright 2015, 2016 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+const leading0x = /^0x/;
+
+const etherscanUrl = (hash, isTestnet) => {
+  hash = hash.toLowerCase().replace(leading0x, '');
+  const type = hash.length === 40 ? 'address' : 'tx';
+
+  return `https://${isTestnet ? 'testnet.' : ''}etherscan.io/${type}/0x${hash}`;
+};
+
+export default etherscanUrl;