main: now references index.js

because i expect the user to be using commonjs by default
If the user was using script tags then this will not matter at all.

package.json

@@ -2,7 +2,7 @@
   "name": "justgage",
   "version": "1.2.2",
   "description": "JustGage is a handy JavaScript plugin for generating and animating nice & clean gauges. It is based on Raphaël library for vector drawing, so it’s completely resolution independent and self-adjusting.",
-  "main": "justgage.js",
+  "main": "index.js",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },