pkgs: cleanup deps (drop esprima, update mocha, etc)

Author: Alexej Yaroshevich

package.json

@@ -27,16 +27,17 @@
     "jsdoctypeparser": "^1.1.3"
   },
   "devDependencies": {
-    "browserify": "~3.30.2",
-    "chai": "^1.9.1",
-    "esprima": "^1.2.2",
-    "jscs": ">=1.8.0 <2.0",
-    "jshint": "~2.5.4",
-    "mocha": "~1.17.1"
+    "chai": "^1.10.0",
+    "jscs": "^1.8.0",
+    "jshint": "^2.5.10",
+    "mocha": "^2.0.1"
   },
   "peerDependencies": {
     "jscs": ">=1.8.0 <2.0"
   },
+  "optionalDependencies": {
+    "browserify": "^6.3.3"
+  },
   "scripts": {
     "lint": "jshint lib test && jscs lib test",
     "test": "npm run lint && mocha",