Major upgrade of libdataset

This release brings py_dataset up to libdataset v0.1.6. Much has changed including breaking changes.
Google Sheet, S3, Google Cloud Storage integration has been dropped. Functions that only returned a error string now return True on success and False otherwise. The error string is available with dataset.error_message(). Namaste functions have been added for a collection's metadata. Deplicate function defs have been removed. A few functions got renamed, overloaded functions got split into separate ones (e.g. frames became frame_create(), for creation and frame() to read a frame's full metadata). grid() function has been removed (use frame_create() and frame_grid() instead).

Windows support still has some testing issues so should be considered experimental. macOS and Linux are passing test.