Added support for opacity to borders.
Added support for opacity to borders.

joshuabrown-ellation/libjass,Dador/libjass,Dador/libjass,Arnavion/libjass,joshuabrown-ellation/libjass,Arnavion/libjass,Dador/libjass,joshuabrown-ellation/libjass,Arnavion/libjass