Issue #15: Add Solr indexing support for variants
Added count method to the AbstractSolrService.
Issue #33: Add JQPL to Solr query translator
Fixed translator to allow queries which return complete entities to work properly.
Issue #19: Create an abstraction layer for managing JPQL queries
Added count support.
Issue #33: Add JQPL to Solr query translator
Added default query in case no fields are specified.
Issue #33: Add JQPL to Solr query translator
Added support for BETWEEN expressions.