Zap some generic code that wasn't going anywhere

src/ebml.rs

@@ -1,5 +1,4 @@
 use bytes::{BigEndian, ByteOrder, BufMut};
-use futures::Async;
 use std::error::Error as ErrorTrait;
 use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::io::{Cursor, Error as IoError, ErrorKind, Result as IoResult, Write, Seek, SeekFrom};
@@ -251,12 +250,6 @@ pub trait FromEbml<'b>: Sized {
     }
 }
 
-pub trait EbmlEventSource<'a> {
-    type Event: FromEbml<'a>;
-    type Error;
-    fn poll_event(&'a mut self) -> Result<Async<Option<Self::Event>>, Self::Error>;
-}
-
 #[cfg(test)]
 mod tests {
     use bytes::{BytesMut};