Demo application for Solr Input Output Operators.

Use case for demo:
InputItemGenerator generates random objects of product info (considering these products are searched/purchased/watched by customers on some e-commerce site). Solr Output operator stores this information into solr server for future usage.
SolrInput operator keeps reading information from Solr server using time based query and generates result for top n products which have been searched/purchansed/watched in last x minutes.