Restructuring xfer top-level folders

[adamian]

Issue #, if available:

Description of changes: Summary: Restructuring xfer such that it becomes a more general Python repository for transfer and meta-learning. The previous state of xfer now becomes a sub-folder named xfer-ml which is only one of the tools contained in the now more general project xfer. Currently xfer-ml is the only library, but soon more will be added (hence the need for restructuring).

Details:

• Created xfer-ml subfolder
• Moved all files and folders (apart from NOTICE and CODE_OF_CONDUCT) inside xfer-ml with no further changes
• Re-wrote top-level README.md and xfer-ml/README.md to reflect the new nature of the structure.

In essence, only the new README's have content changes, the rest of the changes is just files moved to the new xfer-ml folder.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[adamian]

Can you move the LICENSE file to the top level of the repo please?

Done