v0.6.0


features

* consistently return dataset IDs as a separate key (pld)
    * API change if anything relies on the IDs being inside strings, they should be easier to extract as separate key/values


fixes/maintenance

* correctly encode nested MongoDB queries (pld, rgaudin)
* return a proper error message when joining datasets with overlapping columns (rgaudin)
* update celery, pandas, pymongo (pld)
* on update do not replace dframe and other performance related fixes and refactoring (pld)