add DELE command for delete file. (#46)

Author: yackushevas

src/ftp.rs

@@ -82,7 +82,7 @@ impl FtpStream {
         };
         self.secure_with_ssl(ssl)
     }
-   
+
     /// Switch to a secure mode if possible, using a provided SSL configuration.
     /// This method does nothing if the connect is already secured.
     ///
@@ -447,6 +447,14 @@ impl FtpStream {
         Ok(())
     }
 
+    /// Remove the remote file from the server.
+    pub fn rm(&mut self, filename: &str) -> Result<()> {
+        let rm_command = format!("DELE {}\r\n", filename);
+        try!(self.write_str(&rm_command));
+        try!(self.read_response(status::REQUESTED_FILE_ACTION_OK));
+        Ok(())
+    }
+
     fn put_file<R: Read>(&mut self, filename: &str, r: &mut R) -> Result<()> {
         let stor_command = format!("STOR {}\r\n", filename);
         let mut data_stream = BufWriter::new(try!(self.data_command(&stor_command)));