Display modified date, author and revision for directory listings in FishEye

Inspired by the Answers post by Stephen Lecheler: https://answers.atlassian.com/questions/244310/fisheye-subversion-and-directory-updates-who-what-revision-when?page=1#244473

Investigate the performance impacts of displaying the following three fields for directories, as we currently do for files.

• modified date
• author
• revision id

Investigation already by bhumphreys has revealed that is appears we are already storing these attributes on directory nodes, so the prognosis is good.