bugfix: fixed layout spine item documents should not have overriden styles, see https://github.com/readium/readium-js-viewer/issues/593
bugfix: fixed layout spine item documents should not have overriden
styles, see https://github.com/readium/readium-js-viewer/issues/593

ravn-no/readium-shared-js,ravn-no/readium-shared-js,kivuto/readium-shared-js,NYPL-Simplified/readium-shared-js,NYPL/readium-shared-js,NYPL/readium-shared-js,NYPL-Simplified/readium-shared-js,JoMedia/readium-shared-js,readium/readium-shared-js,readium/readium-shared-js,kivuto/readium-shared-js