Experimenting with per-annotation edit locking.  Hacking it via comments, and "locking" on client based on "LOCKED BY" comments.
Added lock/unlock items to feature context menu.  Added experimental private setting, hacked through comments.  Added make-private/make-public items to feature context menu.
Added feature label styling for self-locked, other-locked, and private features.
Modified HTMLFeatures.addFeatureToBlock to handle case where no featDiv is returned by renderFeature (such as filtering out of featDivs in renderFeature in a subclass)