support getBlankEvent() function.

index.js

@@ -1,6 +1,12 @@
 import {relayConnect} from './relay'
 import {relayPool} from './pool'
-import {signEvent, verifySignature, serializeEvent, getEventHash} from './event'
+import {
+  getBlankEvent,
+  signEvent,
+  verifySignature,
+  serializeEvent,
+  getEventHash
+} from './event'
 import {makeRandom32, sha256, getPublicKey} from './utils'
 
 export {
@@ -12,5 +18,6 @@ export {
   getEventHash,
   makeRandom32,
   sha256,
-  getPublicKey
+  getPublicKey,
+  getBlankEvent
 }