Add transaction.invoiceID setter

src/js/ripple/transaction.js

@@ -268,6 +268,14 @@ Transaction.prototype.destinationTag = function(tag) {
   return this;
 };
 
+Transaction.prototype.invoiceID = function(id) {
+  if (typeof id === 'string') {
+    while (id.length < 64) id += '0';
+    this.tx_json.InvoiceID = id;
+  }
+  return this;
+};
+
 Transaction._pathRewrite = function(path) {
   return path.map(function(node) {
     var newNode = { };
@@ -630,20 +638,22 @@ Transaction.prototype.submit = function(callback) {
 
   this.callback = typeof callback === 'function' ? callback : function(){};
 
-  function submission_error(error, message) {
+  function submissionError(error, message) {
     if (!(error instanceof RippleError)) {
       error = new RippleError(error, message);
     }
     self.callback(error);
   };
 
-  function submission_success(message) {
+  this.once('error', submissionError);
+
+  function submissionSuccess(message) {
     self.callback(null, message);
   };
 
+  this.once('success', submissionSuccess);
+
   this.on('error', function(){});
-  this.once('error', submission_error);
-  this.once('success', submission_success);
 
   var account = this.tx_json.Account;