added .js to main property in package.json

package.json

@@ -4,7 +4,7 @@
   "description": "Logic-less {{mustache}} templates with JavaScript",
   "author": "mustache.js Authors <http://github.com/janl/mustache.js>",
   "keywords": ["mustache", "template", "templates", "ejs"],
-  "main": "./mustache",
+  "main": "./mustache.js",
   "devDependencies": {
     "vows": "0.6.x",
     "uglify-js": "1.3.0"