internal/v4: add cache-control headers for archive GET
Merge pull request #207 from rogpeppe/090-cache-control

internal/v4: add cache-control headers for archive GET

This will allow the client to know that it can cache the archive files.
internal/router: add fullySpecified parameter to IdHandler

Also add selective caching to internal/v4.
Merge pull request #208 from rogpeppe/091-fully-specified-idhandler

internal/router: add fullySpecified parameter to IdHandler

We also change internal/v4 so that the Cache-Control header is only added when the id is fully specified.
internal/v4, internal/router: use concurrency
Merge pull request #210 from rogpeppe/092-changes

internal/v4, internal/router: use concurrency

This might speed up search results considerably.
internal/v4: add forgotten comment from PR #210
Merge pull request #211 from rogpeppe/093-add-forgotten-comment

internal/v4: add forgotten comment from PR #210

Forgot to write the file before pushing.
denormalise name in elasticsearch; add id endpoints
Merge pull request #213 from rogpeppe/094-denormalise-id

denormalise name in elasticsearch; add id endpoints

We don't need to denormalise the id-related data in the entity mongo doc
yet, although that will be easy to add later if/when required.