Horst is a simple script to change the fps of a .srt file.
ruby horst.rb subtitle.srt 25 23.976 will convert subtitle.srt from 25 fps
to 23.976 fps and output it.
As .srt file does not contain any information on the fps they are using, this
is your job to find this value. This is usually displayed on the website where
you downloaded the file.