Added shortcut from compass to map by a single click

Now you can switch with just a single click between compass and map - and back.

You switch from compass to map by clicking on the compound info box at the top of the compass containing the destination coordinates and the cache info. From map to compass you can return also with just a single click on the back button - this has not changed.

I think that this is a very useful feature for those who often switch between map and compass.