Commit log should properly sort commits chronologically

When viewing a log with multiple branches, SmartGit often shows the commits non-chronologically. SmartGit should always show commits in chronological order whenever possible. (Obviously in some cases, such as when history is modified, it may be impossible to show commits in chronological order while maintaining proper parent-child ordering, but SmartGit seems to show commits non-chronologically even when not necessary.)

Here's an example where SmartGit is showing commits non-chronologically: