SQL Indexing: tests now run if a postgresql server can be reached

Using org.qi4j.test.util.Assume.assumeConnectivity(..)
SQL Indexing: @Ignore tests on Enums and NeSpecification (not supported)
QI-387 Add tests for Queries on Date and JodaTime Properties

OpenRDF and ElasticSearch Indexing support queries on dates.
SQL Indexing fails ....

ElasticSearch does automatic TimeZone resolution when querying on
DateTimes which leads to a sublet different behavior, see QI-387.

Tests are now in place and skipped in SQL Indexing.