Tmtk

* More easily extensible validator functionality
* Added multiple validation methods
* Fix issue with namespace cleaner

* Replaced deprecated pandas functionality
* More reliably start batch job

* Create studies from TraIT data templates, see :ref:`data_templates`.
* Create fully randomized studies of any size: ``tmtk.toolbox.RandomStudy``.
* Load data right from Jupyter using transmart-batch, with progress bars!! Also works in
as a command line tool ``transmart-batch``.
* Set name and id from the main study object.

* Minor bug fix for Arborist installation

* The Arborist is now implemented as a Jupyter Notebook extension
* Metadata tags are automatically sorted in Arborist.

* Create and apply tree templates in Arborist
* Improved interaction with metadata tags in Arborist
* Resolved issues with the validator
* R is now an optional dependency