Only index latest charm version.

Use elasticsearch versioning to make sure that only
the latest version of the charm or bundle is indexed.
Therefore only returning the latest version in search
results.
Merge pull request #178 from mhilton/search-index-only-latest-version

Only index latest charm version.

Use elasticsearch versioning to make sure that only
the latest version of the charm or bundle is indexed.
Therefore only returning the latest version in search
results.
internal/v4: implement API endpoint for bundle diagram.svg
Merge pull request #183 from rogpeppe/074-bundle-svg

internal/v4: implement API endpoint for bundle diagram.svg

This requires some QA behind a real web server to
verify that the generated SVGs actually work!
internal/mongodoc: add Contents field to mongodoc.Entity

This will allow us to gain quick access to selected files
in an entity's archive such as README and icon.svg.
Merge pull request #184 from rogpeppe/077-zip-contents

internal/mongodoc: add Contents field to mongodoc.Entity

This will allow us to gain quick access to selected files
in an entity's archive such as README and icon.svg.

We'll actually use the field in an upcoming PR.