HS core:
✓ port: initial port
✓ fix: JS code cleanup (remove hardcoded hacks)
✓ fix: title + description (i.e. something's off with the theme wrapper)
✓ fix: #value_callback may be necessary? (see file.module) OR: ensure #return_value works
✓ fix: #element_validate callback: _hierarchical_select_validate() — verify this still works
✓ port: support multiple HS on the same page
✓ port: admin UI
✓ port: "dropbox" support
- port: "create new item" support
- port: render_flat_select support
- upgrade path: delete cache_hierarchical_select
- upgrade path: documentation
- port: client-side caching (use _hierarchical_select_json_convert_hierarchy_to_cache())
- port: status report
- feature: live preview of HS on the common config form
- refactor: use the proper #value_callback -> #process callback -> #after_build callback pipeline as described in the documentation for form_builder() in form.inc

Taxonomy:
✓ port: admin UI
✓ port: "dropbox" support
- port: taxonomy term form should be altered to include HS
- port: "save lineage" support (i.e. support multiple parents, automatic warning shown through hs_taxonomy_hierarchical_select_root_level())
- port: "create new item" support
- refactor: use the vocabulary machine name internally instead of the vid
- upgrade path: migrate settings
- upgrade path: documentation
- port: field formatters (from content_taxonomy)
- port: token support
- refactor: optimize HS API implementation: take advantage of improvements in Taxonomy

HS Taxonomy Views: 
- everything

Menu: 
- everything

Flat List:
✓ everything

Small Hierarchy:
✓ everything