Relax check style trailing whitespace a bit

• Eclipse leave a single trailing whitespace in javadoc comment "blank lines"; it's now allowed
Add Housekeeper to track and cleanup leaked JDBC objects

• Replaces finalizer functionality
• Logs warning when leaked objects are cleaned
Merge branch 'develop' of https://github.com/impossibl/pgjdbc-ng into develop

• Removed finalizers and their replacement (aka the Housekeeper)