Fix global Papa var name

That was a really bad slip.

papaparse.js

@@ -20,12 +20,13 @@
 	else
 	{
 		// Browser globals (root is window)
-		root.returnExports = factory();
+		root.Papa = factory();
 	}
 }(this, function()
 {
 	'use strict';
 
+	var global = Function('return this')();
 	var IS_WORKER = !global.document && !!global.postMessage,
 		IS_PAPA_WORKER = IS_WORKER && /(\?|&)papaworker(=|&|$)/.test(global.location.search),
 		LOADED_SYNC = false, AUTO_SCRIPT_PATH;