Visible view is relocated to centre on the clicked position on overview window

Clicking on a position in the overview window in earlier versions of Jalview would relocate the view so the clicked position was at the top-left corner of the alignment window. This means the user needs to mentally calculate how far away from their region of interest they need to click in order to view that region.

Instead - the view should just be centred on the clicked position.

See this thread:
http://www.compbio.dundee.ac.uk/pipermail/jalview-dev/2017-July/000669.html