consensus/clique: Proof of Authority (#3753)

This PR is a prototype implementation of plugable consensus engines and the
Clique PoA protocol ethereum/EIPs#225

internal/web3ext/web3ext.go

@@ -20,6 +20,7 @@ package web3ext
 var Modules = map[string]string{
 	"admin":      Admin_JS,
 	"chequebook": Chequebook_JS,
+	"clique":     Clique_JS,
 	"debug":      Debug_JS,
 	"eth":        Eth_JS,
 	"miner":      Miner_JS,
@@ -29,8 +30,10 @@ var Modules = map[string]string{
 	"shh":        Shh_JS,
 	"swarmfs":    SWARMFS_JS,
 	"txpool":     TxPool_JS,
+
 }
 
+
 const Chequebook_JS = `
 web3._extend({
   property: 'chequebook',
@@ -63,6 +66,44 @@ web3._extend({
 });
 `
 
+const Clique_JS = `
+web3._extend({
+  property: 'clique',
+  methods:
+  [
+		new web3._extend.Method({
+			name: 'getSnapshot',
+			call: 'clique_getSnapshot',
+			params: 1,
+      inputFormatter: [null]
+		}),
+    new web3._extend.Method({
+      name: 'getSigners',
+      call: 'clique_getSigners',
+      params: 1,
+      inputFormatter: [null]
+    }),
+		new web3._extend.Method({
+			name: 'propose',
+			call: 'clique_propose',
+			params: 2
+		}),
+		new web3._extend.Method({
+			name: 'discard',
+			call: 'clique_discard',
+			params: 1
+		})
+  ],
+	properties:
+	[
+		new web3._extend.Property({
+			name: 'proposals',
+			getter: 'clique_proposals'
+		}),
+	]
+});
+`
+
 const Admin_JS = `
 web3._extend({
 	property: 'admin',