export TX types ... for cosign

Script.js

@@ -40,6 +40,12 @@ function spec(b) {
   };
   this.class = Script;
 
+	Script.TX_UNKNOWN=TX_UNKNOWN;
+	Script.TX_PUBKEY=TX_PUBKEY;
+	Script.TX_PUBKEYHASH=TX_PUBKEYHASH;
+	Script.TX_MULTISIG=TX_MULTISIG;
+	Script.TX_SCRIPTHASH=TX_SCRIPTHASH;
+
   Script.prototype.parse = function () {
     this.chunks = [];