Adding rollback before closing

Empty int64array should not result in scan error

Removing temporal hack for using Peter's branch.

Closing the transaction connection after a successful commit

Trying again after a small delay instead of giving up when no more connections are available.

MySQL: Trying again after a small delay instead of giving up when no more connections are available.

PostgreSQL: Trying again after a small delay instead of giving up when no more connections are available.

order to release it to the pool. Closes #108.

Issue 103 - prepareStatement() must return the generated query

Issue 57 - Provide Driver() method for SQL database transactions.

Issue 80 - Adding cache for C() and benchmarks.

prepareStatement() must return the generated query for debugging purposes even if the query contains a syntax error.

Provide Driver() method for SQL database transactions. This can be used to execute raw SQL queries within a transaction block. Closes #57.

Adding C() as a short-hand for Collection().

This reverts commit 90bca12c.