fixed issue with #EXTINF without titles

in #EXTINF tag, when comma `,` after segment duration immediately follows by `\n` the `title` is not getting populated and is not printed with `writeln!`

The problem is created by the nom 5 conversion, where `take_until_either_and_consume!` macro was replaced with `is_not!` + `take!(1)`. However, in case when `opt!(take_until_either_and_consume!` is used, everything gets way too hairy. I couldn't to expressed that in a fairly elegant manner and instead fixed the data presentation, when a new manifest is produced. While storing `\n` in a form of `title` is a nice hack, I'm also convinced this is a better approach to data handling.

src/playlist.rs

@@ -622,6 +622,8 @@ impl MediaSegment {
 
         if let Some(ref v) = self.title {
             writeln!(w, "{}", v)?;
+        } else {
+            write!(w, "\n");
         }
 
         writeln!(w, "{}", self.uri)