some simple test tunnings
handle ruby dates prepared statement parameters correctly
fix Bignum param being set once again as Integer + allow disabling traces
convert Derby's `_execute` to ruby + extract IS NULL suble into a method
seems that Derby (as well as SQLIte3) lies about generated-keys support
only hookup SQL checks on #execute when no #exec_query etc .available
if there are no results it does not mean keys have been (for sure) generated
re-built jar