File System Changes

In general, external file modifications will be detected immediately in the `Config` object when a watcher thread is enabled (explained later).
Otherwise, they are detected when a commit is performed.

The `Config` object maintains an in-memory record of all changes that have been applied to it through getters and setters.
When the underlying file changes, the new contents are loaded and the in-memory changes are then applied to the new configuration.
This provides the benefits of real-time updates of configurations while not losing any changes made in the JVM.

If the `commit()` method is called on the `Config` objects after the file system contents have been modified, we will then reload the configuration from the file system, apply the changes, and then try to save to the file system again (up to 10 times).

If the same entry is both internally and externally modified, the external modification will be overwritten (although both change events will be seen by listeners).