Code box improvements

This shows the buttons select and download in lower right corner of a pre box.

Select button will select the complete code so that the user can copy it into the clipboard. Tested with Chrome, Firefox and IE8+.

Download button will download the complete code into a file with the format "[url file name]-Script.ahk"; including a BOM. Works only in HTML5-able browsers (because of the added download attribute) and IE10+.