Remove outdated comments
Make tag serialization explicit and symmetrical

This has actually added some redundant code but eliminates a potential time
bomb by removing dependency on the implicit magic of Sequel HStore serializing
non string hash values.
This is not Finder-Frontend
Architecture README notes
Merge pull request #26 from alphagov/architecture-docs

Architecture docs
Don't expose context to extract_params method
Flatten aspect/service composition

+@evilstreak
Merge pull request #25 from alphagov/symmetrize-persistence-mapper

Symmetrize persistence mapper
Merge pull request #28 from alphagov/flatten-service-pyramid

Flatten service pyramid
Extract ResponderProxy from persistence aspect

Clean up and generalise adding callbacks to the responder object