update timeframe `evaluate.py`

[keighrim]

Because

Related to #43 , we want to update now outdated evaluate.py under TF_eval directory. However, since the time when the script is written, there has been some changes regarding gold data organization. So we need to updated the script to cope with those changes.

Done when

This should include

1. updating to use goldretreiver.py instead of manual download of gold files
   • example of usage of the goldretriver https://github.com/clamsproject/aapb-evaluations/blob/55b53e8c2e12a066c4ab1604b38aa4d7cacec355/ocr_eval/evaluate.py#L153
   • should copy or symlink the goldretriver.py first

     $ cd timeframe-eval 
     $ ln -sf ../goldretriever.py

2. merging following two functions https://github.com/clamsproject/aapb-evaluations/blob/55b53e8c2e12a066c4ab1604b38aa4d7cacec355/timeframe-eval/evaluate.py#L56 https://github.com/clamsproject/aapb-evaluations/blob/55b53e8c2e12a066c4ab1604b38aa4d7cacec355/timeframe-eval/evaluate.py#L76

   • the "gold" files for chyron and slate annotation have been updated since the original eval.py script is written.
   • old chyron gold
   • current chyron gold
   • old slate gold
   • current slate gold
3. Update start and end properties access with newly added helper methods via https://github.com/clamsproject/mmif-python/pull/254

Additional context

No response