Remove npm build script and add dev dependencies "grunt" and "coffee-script".

 .DS_Store
 *.swp
+node_modules/**/*

@@ -12,7 +12,8 @@
     "type" : "git",
     "url" : "https://github.com/mikeric/rivets.git"
   },
-  "scripts" : {
-    "build" : "coffee -o lib -c src"
+  "devDependencies" : {
+    "grunt" : "0.3.x",
+    "coffee-script" : "1.3.x"
   }
 }