Remove es5: true setting from /.jshintrc

This setting throws an error in JSHint 2.0.0 and above, as explained by
http://jslinterrors.com/es5-option-is-now-set-per-default

Author: emlun

.jshintrc

@@ -10,6 +10,5 @@
 	"unused": true,
 	"boss": true,
 	"eqnull": true,
-	"node": true,
-	"es5": true
+	"node": true
 }