$# Cleaning up installation lang file + reinstating the Javascript error + some

As of today, we have many lang strings which are not used during installation. These are remnants of 2.5.
Also, we do not check anymore in 3.x if javascript is enabled in the browser. 
This patch reinstates the check and will display an alert if not. It also deletes and reorder the lang strings in en-GB, en-US and en-AU