docs: update data descriptor.rst
docs: revamp index
update dependencies
docs: revamp overview
docs: correct column names in data
docs: remove name of file from csv content
docs: walk over index again
docs: simple install instructions with conda
docs: walk over overview again
docs: small edits to data_descriptor
docs: rename data, add current state
add expressions doc
add backends
docs: remove datashape docs, link to datashape.pydata.org
docs: remove old documents from index
minor edit
api: add into
api: into works given type as first argument
data: into
data: potential columns attribute on data descriptors