proposing dataset-orm as an add on

[miraculixx]

I needed an ORM-like front-end to dataset, so I made one. dataset-orm also includes a files-column type and API that supports storing files of arbitrary size using simple put()/get() semantics.

If you like it happy to merge or perhaps it's better to keept it as a seperate add-on

PyPi https://pypi.org/project/dataset-orm
GitHub https://github.com/productaize/dataset-orm

#308