The new dream in computing is keeping all of your files in "the cloud," on remote servers that you can access from anywhere at any time. Apple's cloud-based syncing and storage service, iCloud, debuted in June 2011. Still, only since the release of OS X Mountain Lion that enough applications have started to support iCloud document syncing for this feature to be useful. Working with iCloud is fairly simple, but you need to know the ground rules if you plan to start storing your documents in the cloud. …