Match 'int' as well as 'integer' when converting to SQL types for MSSQL
[derby] support getting and setting transaction isolation on a connection

setting it using the JDBC method seems to avoid some probable locking :

SQLException: Column 'PARAM1' already exists. SQL State: X0Y68

(likely related to #497 as well)
[derby] allow to configure whether :transaction_isolation will be 'serializable'
development @ 1.3.6.DEV
try one more gem update system trick with travis-ci
improve rake test (desciptions)
only do the patched select_limited_ids if connection is Derby's
update test-unit-context - contains a patch for a bug in latest test-unit 2.5.5
update jdbc-h2 to 1.3.175
Handling of 'GROUP BY' and selected columns

1. Ensure correct queries if the rest_of_query contains a 'GROUP BY'.
2. Create a correct subquery if there's only one id column.
Partially fixes #437
SELECT DISTINCT clause with ORDER BY for MSSQL

SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.

Partially fixes #437
[mysql] support "disabling" abandoned connection cleanup thread

due leaks on hot re-deploys - will probably be shutdown by default on the next major version or AR-JDBC
re-build jar using JRuby 1.6.8 on Java 6