Online storage service enhancements help it keep pace with rivals like DropBox, Apple’s iCloud, and Google Drive. By Paul McDougall Microsoft has unveiled a major revamp of SkyDrive, and said the cloud storage service has moved beyond the “preview” stage to become fully operational. The enhancements include a new Web front, faster uploading and sorting, new tools for developers, and a forthcoming SkyDrive app for mobile devices that run Google Android.