The provided sphinx search is bad because:

• Only searches the current doc at the current version
• Only reads Sphinx metadata

To resolve this, three milestones:

• Search all tracked docs (done for v0.4.8, most relevant commit is a76a462)
• Filter versions
• Add multi metadata adapters to search.js (e.g. digest some doxygen dict) and/or learn how to convert arbitrary metadata into sphinx searchindex.js format.

Tricky part:

• move search.js from app.js to extra.js, without breaking older docs (done).