Move test flags from JSON to commandline

[ptr727]

Move test flags to commandline options.
Too easy to forget to reset the flag and modify production content.

    // Create short video clips, useful during testing
    // Note the media files will be overwritten with short clips
    "TestSnippets": false

  "ProcessOptions": {
    // Do not make any modifications, useful during testing
    "TestNoModify": false,