[DB2] tests for time quoting
prepared statement support for exec_update / exec_delete
fails without columns in binds using prepared statements (on PostgreSQL)
support for returning multiple generated keys + rename unmarshal methods

also make sure we always check if generated keys are supported and return null otherwise
pass runtime directly to getResultHandler instead of context
cleanup sqlite_version >= matching - our gem jdbc_sqlite3 >= 3.5
... and fix matching in supports_savepoints? '3.6.10' should be >= '3.6.8'
test for #422 - which currently needs a jdbc-sqlite3 pre-release to pass
store config in a local variable outside loop
exec_insert - prepared statements + fix logging with bind params
compat: even if generated keys supported but none return update count
expecting a single id (generated key) here
did not account for empty generated keys while refactoring
[postgres] support exec_insert with PS + make sure RETURNING works
as it needs some hand-tunning on AR <= 3.2 (AR 4.0 finally got it right)
also with Postgre's JDBC driver we can not use generated keys currently
[postgres] allow nil with last_inserted_id (due disabled generated keys)
better `last_inserted_id` unwrapping on the base adapter level
improve timestamp/time/date values sent to JDBC from prepared stmnts
[sqlite] a saner way of getting last_insert_row_id() via the JDBC API
[sqlite] query-ing last_insert_id after each INSERT stmnt seems redundant
[sqlite] also avoid last_insert_id query after INSERT on AR-2.3
improve nanos handling since `microseconds` returns more than expected