Don't re-centre map if user moves it.

If the user has moved the 'pin area', please don't re-centre the map when they change date. We have to move the pin off to one side to avoid the (very useful) 'help' window. There is just enough clear screen to see the whole of the 'pin area' but if you enter a new date, the map re-centers and you have to move it into the clear all over again. Just leave the 'pin area' (centred on the user's physical location) in whatever [x,y] position it finds itself following their move. You can then display the newly-calculated sun lines there. Thank you!