fixed #10861 - Zoom to layer when opening new file (see #10860)


git-svn-id: https://josm.openstreetmap.de/svn/trunk@7817 0c6e7542-c601-0410-84e7-c038aed88b3b
see #10837 - add some more validation rules (based on rules by naoliv)

git-svn-id: https://josm.openstreetmap.de/svn/trunk@7818 0c6e7542-c601-0410-84e7-c038aed88b3b
fix #10851 - add validator warning for `sidewalk=*` together with `foot=no`, workaround for another validator message

git-svn-id: https://josm.openstreetmap.de/svn/trunk@7819 0c6e7542-c601-0410-84e7-c038aed88b3b