Don't escape special characters, as we'll send the buffer as
text/plain rather than text/x-pango-markup; this avoids e.g.
quotes from appearing as " in the rendered subtitles.
See bug #600929.
katedec: Kate decoder (text only)
kateenc: Kate encoder (text and DVD SPU only)
katetag: Kate tagger
kateparse: Kate parser
tiger: Kate renderer using the Tiger rendering library
Fixes#525743.