Connection: default value for sendGetBlocks

Connection.js

@@ -186,10 +186,15 @@ Connection.prototype.sendVersion = function () {
 };
 
 Connection.prototype.sendGetBlocks = function (starts, stop, wantHeaders) {
+  // Default value for stop is 0 to get as many blocks as possible (500)
+  stop = stop || '00000000000000000000000000000000';
+
   var put = new Put();
-  put.word32le(this.sendVer);
 
+  // https://en.bitcoin.it/wiki/Protocol_specification#getblocks
+  put.word32le(this.sendVer);
   put.varint(starts.length);
+
   for (var i = 0; i < starts.length; i++) {
     if (starts[i].length != 32) {
       throw new Error('Invalid hash length');