Fix multiline cue text error.

The problem was that we were ending on any line that ends with a newline
character. Therefore, we would only parse one line of cue text. I've
set it up so that it ends parsing cue text on a line that is either
empty or consists of only a new line character.
Merge remote-tracking branch 'reyre/multiline-fix-2' into plformat
Fix multiline cue text error.

The problem was that we were ending on any line that ends with a newline
character. Therefore, we would only parse one line of cue text. I've
set it up so that it ends parsing cue text on a line that is either
empty or consists of only a new line character.
Merge branch 'multiline-fix-2' of https://github.com/RickEyre/webvtt into multiline

Line-wraps comment.
Merge branch 'multiline' into plformat
Fix multiline cue text error.

The problem was that we were ending on any line that ends with a newline
character. Therefore, we would only parse one line of cue text. I've
set it up so that it ends parsing cue text on a line that is either
empty or consists of only a new line character.
Fix multiline cue text error.

The problem was that we were ending on any line that ends with a newline
character. Therefore, we would only parse one line of cue text. I've
set it up so that it ends parsing cue text on a line that is either
empty or consists of only a new line character.
Merge branch 'multiline' into plformat