fix #35, add pkijs, node.extend, asn1

package.json

@@ -1,6 +1,6 @@
 {
   "name": "letsencrypt",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "description": "Let's Encrypt for node.js on npm",
   "main": "index.js",
   "scripts": {
@@ -35,10 +35,13 @@
   },
   "optionalDependencies": {},
   "dependencies": {
+    "asn1": "^0.2.3",
     "bluebird": "^3.0.6",
     "homedir": "^0.6.0",
     "letiny-core": "^2.0.1",
     "mkdirp": "^0.5.1",
+    "node.extend": "^1.1.5",
+    "pkijs": "^1.3.27",
     "pyconf": "^1.1.2",
     "request": "^2.67.0",
     "rsa-compat": "^1.2.1",