v0.3.0

Backwards-incompatible changes

• All of the top-level document attributes (author, date, etc.) are now grouped under the
  "properties" key of the org-document object.
• Export start property of timestamp nodes with the correct name. Was being exported with the
  name begin.
• JSON objects representing generic key/value mappings no longer have the "$$data_type" property.

Features

• Data in property drawers is now exported with headlines in the "drawer" property.

Other

• Now requires Emacs 26.1.
• Reorganized/cleaned up much of the internals.