feat: added '--sub-alignment' arg. This can control the position of the subtitles for everything that isn't a "sync" frame
refactor: removed --index-dir arg feat: added --source-index-path and --encode-index-path, these are direct paths to the index file vs only having a directory to search refactor: added a more descriptive help message for --subtitle-color
feat: added support for specific frames being passed via the --frames arg. This should be a single string separated by : like so "1001:1002"
