Added npm uninstall

Author: shazron

package.json

@@ -1,11 +1,12 @@
 {
   "name": "ios-sim",
-  "version": "1.8.0",
+  "version": "1.8.1",
   "description": "launch iOS apps into the iOS Simulator from the command line (Xcode 4)",
   "main": "ios-sim",
   "scripts": {
-    "install": "rake install"
+    "preinstall": "rake build"
   },
+  "bin" : "build/Release/ios-sim" ,
   "repository": {
     "type": "git",
     "url": "https://github.com/phonegap/ios-sim"