chore(package): add benchpress dependencies and remove unused gulp dependencies

Author: jeffbcross

package.json

@@ -34,7 +34,14 @@
   "homepage": "https://github.com/ReactiveX/RxJS",
   "devDependencies": {
     "babelify": "^6.1.2",
-    "gulp": "^3.8.11",
-    "gulp-run": "^1.6.8"
+    "benchmark": "^1.0.0",
+    "benchpress": "^2.0.0-alpha.25",
+    "http-server": "^0.7.5",
+    "jasmine-core": "^2.2.0",
+    "lodash": "^3.5.0",
+    "platform": "^1.3.0",
+    "protractor": "^1.7.0",
+    "requirejs": "^2.1.16",
+    "rx": "^2.4.3"
   }
 }