break backwards compat for acme-v2

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rsa-compat",
-  "version": "1.3.1",
+  "version": "2.0.0",
   "description": "RSA utils that work on Windows, Mac, and Linux with or without C compiler",
   "main": "node.js",
   "bin": {