Update README.md with more about deploying the CloudReader
Update README.md with more about deploying the CloudReader

Updated README.md with info about not trying to load resource from zipped EPUBs with the CloudReader, along with a link to the document that provides additional detail.
readium/readium-js-viewer,AndyHubert/readium-js-viewer,AndyHubert/readium-js-viewer,readium/readium-js-viewer