The AbstractionPlugin abstract class is used as a base plugin when creating
plugins that add the results of an Endeca query to an "AbstractedResult"
object, which can then be marshalled and sent back to the client.
The AggRecordsAbstractionPlugin retrieves aggregated record result set information;
it adds its data to the AbstractedResults object, under the key "AggrRecords".
Simple pre-processor that adds dimension search for the last search
term the user entered (for record search)
TODO: make configurable via injected configuration for things like a specific dimension, opts, etc