various updates

Rename AbstractIndex -> FeatureIndex
Rename UniqueIndex -> UniqueFeatureIndex
Rename SecondaryIndex -> TopKIndex

Initial work pulling in visualeditor JS
Add render method to Block interface
Remove some now-irrelivant commenting
ObjectStorage interface now extends from IteratorAggregate, various arn't fully
implementing it yet and throw exceptions when called.
More consistent error results,  use null instead of false for consistency

Rename lifecycle events, onPostLoad -> onAfterLoad and all similar, to
prevent confusion between Post's to a topic and events that happen after
something

Change-Id: If85dbc1a9c8558e4ec0f5b8c2030f3e08b5dc399