JRuby 1.6.8 compatibility when rescue-ing Java exception
better (simplified) type handling for DB2 + a read-able #zos_create_table
working DB2 binary support - improved quoting + use lob callback for all
since it was failing on BLOB/CLOB  inserts otherwise - backwards compat provided with the ADD_LOB_CALLBACK constant in case this breaks smt
[derby] avoid failures with #quote when second arg nil + keep string enc
only run "global" row locking test on AR >= 3.0
[postgres] test with AR 2.3 behavior - infinite timestamps returned as nils
[postgres] cache quoted_table_name & quoted_column_name values
similar to Rails and how MySQL adapter does this