Default Isolation Level for all Transactions

[marvinscharle]

What this does:

• Adds static attribute defaultIsolationLevel to Transaction (which defaults to the current value ISOLATION_LEVEL.READ_COMMITTED)
• If a user wants to change the isolation level globally for an app, they have to update Transaction.defaultIsolationLevel to the desired isolation level.

Example:

Transaction.defaultIsolationLevel = ISOLATION_LEVEL.READ_UNCOMMITTED

// All transactions will now have the isolation level READ_UNCOMMITTED unless explicitly specified on each transaction

[dhensby]

Thanks, this looks good and really appreciate the tests

[dhensby]

This has been released as v6.2.0