templates: rm unused nulldata code

src/templates/nulldata.js

@@ -1,8 +1,6 @@
 // OP_RETURN {data}
 
 const bscript = require('../script')
-const types = require('../types')
-const typeforce = require('typeforce')
 const OPS = require('bitcoin-ops')
 
 function check (script) {
@@ -13,22 +11,4 @@ function check (script) {
 }
 check.toJSON = function () { return 'null data output' }
 
-function encode (data) {
-  typeforce([types.Buffer], data)
-
-  return bscript.compile([OPS.OP_RETURN].concat(data))
-}
-
-function decode (buffer) {
-  typeforce(check, buffer)
-
-  return bscript.decompile(buffer).slice(1)
-}
-
-module.exports = {
-  output: {
-    check: check,
-    decode: decode,
-    encode: encode
-  }
-}
+module.exports = { output: { check: check } }