Fixed typos in transaction.verify error messages

lib/transaction/transaction.js

@@ -1011,12 +1011,12 @@ Transaction.prototype.verify = function() {
   if (isCoinbase) {
     var buf = this.inputs[0]._script.toBuffer();
     if (buf.length < 2 || buf.length > 100) {
-      return 'coinbase trasaction script size invalid';
+      return 'coinbase transaction script size invalid';
     }
   } else {
     for (i = 0; i < this.inputs.length; i++) {
       if (this.inputs[i].isNull()) {
-        return 'tranasction input ' + i + ' has null input';
+        return 'transaction input ' + i + ' has null input';
       }
     }
   }