updated README with HTTP CORS and cloud reader deployment info
updated README with HTTP CORS and cloud reader deployment info

kivuto/readium-js-viewer,readium/readium-js-viewer,GermanCentralLibraryForTheBlind/readium-js-viewer,NYULibraries/readium-js-viewer,looknear/readium-js-viewer,GermanCentralLibraryForTheBlind/readium-js-viewer,kivuto/readium-js-viewer,looknear/readium-js-viewer,readium/readium-js-viewer,AndyHubert/readium-js-viewer,AndyHubert/readium-js-viewer,NYULibraries/readium-js-viewer