Updater Changes

- Added a "Friendly Name" and "Description" to the Updates tab.
- Uses checksum per file to determine if it has to download a file or
not during updates. Plugins need to update their version.JSON to take
advantage of these changes. Can generate with:

https://github.com/cjmanca/FFXIVDBM.Plugin/blob/master/distribution/GenerateVersionJSON.exe?raw=true