- graphics helper: add movie_extract_frame event to generate function
(allows modules to add to the options sent to movie::extract_frame or to
generate the thumbnail on their own without movie::extract_frame)
- movie helper: add extra optional argument to movie::extract_frame
(can add ffmpeg arguments and/or change the frame extract time)
- gallery_installer: add movie_extract_time module variable, update to v53
- module.info: update to v53
- install.sql: update to v53