Add re-indexing callback from within `FieldBridge` implementations

[jmoore]

Each call to iUpdate.indexObject() or FieldBridge.set() involves a single object. The interface provides the Lucene Document which represents the object. There's no way to access Documents for related objects (like the Images within a Project). A callback should be added to allow such re-indexing.

See: SearchBridges and ticket:954

[jmoore]

One remaining weakness in with this solution will be that when indexing Annotations it will not be possible to navigate to the containing object and schedule them for re-indexing. This holds for all objects which are on the blind side of a unidirectional relationship.

[jmoore]

Incomplete support in r2363

[jmoore]

Is a fairly complex requirement, possibly requiring notifications itself. Pushing.

[jmoore]

r2376

[jmoore]

r2491 solves the issues of annotations. When an annotation link is indexed, the parent gets scheduled for indexing via the ReindexMessage. This still does not solve the blind side of a unidirectional relationship, but if versions don't nothing will.