Emby-updater

* Fixed: getting the right release. In some cases it was possible to get the release instead of the pre-release when the '--beta' option was used.

* Initial release after refactoring from the bash script
* `--beta` option to install the emby beta versions
* `-y`/`--yes` answer yes to all questions during the installation
* `--update` *new* to update the updater script to the latest version
* `--help` shows a helpful ;P help message how to use `emby-updater`