fix Address validation issue

Address.js

@@ -16,6 +16,7 @@ Address.prototype.validate = function() {
     Address.super(this, 'validate', arguments);
     if(this.data.length !== 21) throw new Error('invalid data length');
   });
+  if (typeof this.network() === 'undefined') throw new Error('invalid network');
 };
 
 Address.prototype.isValid = function() {

test/test.Address.js

@@ -35,6 +35,9 @@ describe('Address', function() {
     ['1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz', false], // too long Bitcoin address
     ['1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz', false],// too long Bitcoin address
     ['2cFupjhnEsSn59qHXstmK2ffpLv2', false],        // valid base58 invalid data
+    ['dB7cwYdcPSgiyAwKWL3JwCVwSk6epU2txw', false],  // valid base58, valid length, invalid network
+    ['2MnmgiRH4eGLyLc9eAqStzk7dFgBjFtUCtu', false],  // valid base58, valid length, invalid network
+    ['32QBdjycLwbDTuGafUwaU5p5GxzSLPYoF6', true],  // valid base58, valid length, valid network
   ];
   data.forEach(function(datum) {
     var address = datum[0];

test/test.misc.js

@@ -129,5 +129,13 @@ describe('Miscelaneous stuff', function() {
       });
     }
   });
+  testdata.dataBase58KeysInvalid.forEach(function(datum) {
+    var b58 = datum[0];
+    it('shouldnt be able to create Address nor WalletKey with ' + b58, function() {
+      var a = new Address(b58);
+      var invalidAddress = (!a.isValid());
+      invalidAddress.should.equal(true);
+    });
+  });
 
 });