Add ability to configure to display the caption based on view mode.

Problem/Motivation

Currently image captions appear in all view modes. In some contexts this is now what's desired. For example, a teaser view may include a photo but not its caption.

Proposed resolution

Provide the ability to configure caption display on the Manage Display page for each content type.

In Drupal 7, the preferred solution for modifying the settings of another module's field formatters is to use the Field Formatter Settings → helper module.

To avoid introducing a new dependency, which might require a new branch, implement this as an optional enhancement.

Test for the view mode configuration in a field preprocessor. Also move sanitizing out of the theme functions to that preprocessor.

Remaining tasks

Add an update to clear caches so the new hook implementations are recognized?

User interface changes

Image caption display is configurable per field per view mode.

API changes

Data model changes

Release notes snippet

Introduces the ability to configure image caption display per view mode. This optional enhancement requires the Field Formatter Settings module to be installed.