Storyboard thumbnail support
  - Changed FileProviderImpl to not call Java's createTempFile
  - Added BeanUtils class and CloneField annotation for copying objects
  - Added Mergable annotation
  - Made TransformationOptions and TransformationSourceOptions copyable
and mergable with unit tests
  - Added TimecodeUtils
  - Added support for multiple targets to FFmpeg worker
  - Added support for storyboard thumbnail request to FFmpeg worker
  - Added storyboard integration tests and test file