4.0.0-beta.4

This release drafts the fourth beta version of QDB4.

This version implements a few bug fixes to various parts of the module. Including, but not limited to:

• Documentation type fixes.
• 'Not a database' error when iterating through files.
• 'Null' error when a path was casted in Connection fetch mode.

Secondly, I added or tweaked a couple of features within the package.

• There's a new method added to the Pool class to disconnect from the Connections, <Pool>.Disconnect() -> Pool.
• The Erase() method of Connections has been improved, as now it uses one SQL instructions instead of chaining multiple.
• Pools can now be backed up as a general endpoint for managing copies of the databases.
• As for performance improvements, there's a new IterCache option to customise iteration behaviour of the database.

Finally, I implemented a way for Pools to be run on a separate thread. As to instantiate a Pool with a thread, add the Threaded option and give it a true value to indicate that you want to initialise a worker thread for this Pool. This option will initialise Gateways instead of Connections, and these class instances will communicate with the Pool's ThreadProvider to send instructions and receive data from the worker thread.

It's currently not possible to create multiple threads, but I would consider it in later releases.