Fixes #22 (Removed hardcoded path)

Author: Bruno Herfst

index.js

@@ -25,7 +25,7 @@ extendscriptr.options.forEach(function(opt) {
   );
 });
 
-var prototypePolyfills = fs.readFileSync('./node_modules/extendscript.prototypes/lib/extendscript.prototypes.js', 'utf8');
+var prototypePolyfills = fs.readFileSync(require.resolve('extendscript.prototypes'), 'utf8');
 var browserifyPlugins = [ [ prependify, prototypePolyfills ] ];
 
 var adobeTarget = String(extendscriptr.target).toLowerCase();