Word wrap changeset comment in history dialog

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6519 0c6e7542-c601-0410-84e7-c038aed88b3b
History dialog: make versions navigable with arrow keys up/down

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6520 0c6e7542-c601-0410-84e7-c038aed88b3b