* Add back "Resize to window" link.
* Add Z shortcut for resize to window link (mnemonic: Z for zoom image).
* Resize images to screen width by default on both desktop and mobile.
* Make it so that notes are nested directly inside the .image-container
element with the image, instead of inside a separate .note-container
element. This means .image-container and .note-container are now the
same element. This is so that the size of the .note-container is
driven by the size of the image, which ensures that notes are
automatically resized as the image is resized.
Changes:
* Drop Users.id_to_name.
* Don't cache Users.name_to_id.
* Replace calls to name_to_id with find_by_name when possible.
* Don't autodefine creator_name in belongs_to_creator.
* Don't autodefine updater_name in belongs_to_updater.
* Instead manually define creator_name / updater_name only on models that need
to return these fields in the api.
id_to_name was cached to reduce the impact of N+1 query patterns in
certain places, especially in api responses that return creator_name /
updater_name fields. But it still meant we were doing N calls to
memcache. Using `includes` to prefetch users avoids this N+1 pattern.
name_to_id had no need be cached, it was never used in any performance-
sensitive contexts.
Avoiding caching also avoids the need to keep these caches consistent.
