Add "recent" list to locked workspace

[dunity]

The LockedObjects workspace could benefit from displaying n-number of recent locked/unlocked objects (regardless of their lock state). They could be displayed in a separate list at the bottom of the workspace, and have their portion of the UI enabled/disabled(hidden) via a button/toggle on the front of the workspace. I VERY often find myself wanting to just toggle on/off the same objects, not wanting to go back and forth to the hierarchy (for large hierarchies) while doing so.

[mtschoen-unity]

What about just sorting by when they were locked? We'd need a way of serializing the time. We can try to lump that in when we work out serializing object groups.