add getTransaction method

lib/blockchainexplorer.js

@@ -22,6 +22,7 @@ function BlockChainExplorer(opts) {
   switch (provider) {
     case 'insight':
       var explorer = new Explorers.Insight(url, network);
+      explorer.getTransaction = _.bind(getTransactionInsight, explorer, url);
       explorer.getTransactions = _.bind(getTransactionsInsight, explorer, url);
       explorer.getAddressActivity = _.bind(getAddressActivityInsight, explorer, url);
       explorer.initSocket = _.bind(initSocketInsight, explorer, url);
@@ -31,6 +32,19 @@ function BlockChainExplorer(opts) {
   };
 };
 
+function getTransactionInsight(url, txid, cb) {
+  var url = url + '/api/tx/' + txid;
+  var args = {
+    method: "GET",
+    url: url,
+  };
+
+  request(args, function(err, res, tx) {
+    if (err || res.statusCode != 200) return cb(err || res);
+    return cb(null, tx);
+  });
+};
+
 function getTransactionsInsight(url, addresses, from, to, cb) {
   var qs = [];
   if (_.isNumber(from)) qs.push('from=' + from);