byteorder: fix typos in ReadBytesExt docs

Closes #129
diff --git a/src/io.rs b/src/io.rs
index 76256a1..74cf9dd 100644
--- a/src/io.rs
+++ b/src/io.rs
@@ -43,7 +43,7 @@
     ///
     /// ```rust
     /// use std::io::Cursor;
-    /// use byteorder::{BigEndian, ReadBytesExt};
+    /// use byteorder::ReadBytesExt;
     ///
     /// let mut rdr = Cursor::new(vec![2, 5]);
     /// assert_eq!(2, rdr.read_u8().unwrap());
@@ -69,11 +69,11 @@
     ///
     /// # Examples
     ///
-    /// Read unsigned 8 bit integers from a `Read`:
+    /// Read signed 8 bit integers from a `Read`:
     ///
     /// ```rust
     /// use std::io::Cursor;
-    /// use byteorder::{BigEndian, ReadBytesExt};
+    /// use byteorder::ReadBytesExt;
     ///
     /// let mut rdr = Cursor::new(vec![0x02, 0xfb]);
     /// assert_eq!(2, rdr.read_i8().unwrap());