FreeSWITCH-FS-6836

Merge pull request #770 in FS/freeswitch from FS-8750-1 to master

* commit 'bdeacb1d29d78626474bf53cf8969bf3ea20c751':
  FS-8751 [Conference Play Video Total Time and Current Time]
  FS-8748 FS-8751 check current play_status
  FS-8748 track pdf total pages and current page
  FS-8754 add ability to read high quality PDF
  FS-8750 implement file_seek for video files