Merge pull request #3177 from ProjectMirador/annotations-icon

__tests__/src/actions/annotation.test.js

__tests__/src/components/GalleryViewThumbnail.test.js

__tests__/src/sagas/annotations.test.js

src/components/GalleryViewThumbnail.js

src/containers/GalleryViewThumbnail.js

src/state/actions/action-types.js

src/state/actions/annotation.js

src/state/sagas/annotations.js

src/state/selectors/annotations.js