gantt: sort issues by start date (#7335)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11897 e93f8b46-1217-0410-a6f0-8f06a7374b81
gantt: sort versions by start date (#7335)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11898 e93f8b46-1217-0410-a6f0-8f06a7374b81