Updated manual caption split pattern
Updated manual caption split pattern

Previously, Plyr was using a fixed pattern of '\n\n' to split
contents into captions. This does not always work as some VTT files
contain '\r\n'. This commit checks for both.

dacostafilipe/plyr,amowu/plyr,dacostafilipe/plyr,amowu/plyr,Tronil/plyr,Selz/plyr,sampotts/plyr,robinpoort/plyr