Dataset-related UI nits

Things I noticed while tracking down dataset problems:

• In the admin-mode "List all Datasets", the datasets are sorted by creator by default; seems like an odd choice. I would think sorting by name or project would be better.
• You cannot sort by project by clicking on the header.
• Ditto for creator. You start out sorted by creator, but if you change to something else, you cannot get back.
• On the page for a particular project, it would be nice if there was a "Datasets" tab.
• Ditto for the user page--a tab for Datasets created by that user.