Hookup Jalview-JS clipboard to the browser clipboard

The various text-panes in Jalview don't seem to copy data to/from the browser clipboard (and hence the system clipboard). This looks to be due to interference between Jalview's internal clipboard..

Try eg File->Export Features and then select 'To Window' - the displayed text file can't be copied and pasted to another window or application (but it can be pasted into another Jalview-JS desktop window via the menus).