if a widget is displayed normal, it can now be minimised or maximised; if a widget is minimised it can only be maximised to restore the normal view;
the view status (minimized or normal) is saved within the dashboard layout and will be restored on reload

git-svn-id: http://dev.piwik.org/svn/trunk@5261 59fd770c-687e-43c8-a1e3-f5a4ff64c105