Add some more examples opening a FTPFS in fs.ftpfs module

Author: althonos

fs/ftpfs.py

@@ -363,17 +363,21 @@ class FTPFS(FS):
         Create with the constructor::
 
             >>> from fs.ftpfs import FTPFS
-            >>> ftp_fs = FTPFS()
+            >>> ftp_fs = FTPFS("demo.wftpserver.com")
 
         Or via an FS URL::
 
-            >>> import fs
-            >>> ftp_fs = fs.open_fs('ftp://')
+            >>> ftp_fs = fs.open_fs('ftp://test.rebex.net')
 
         Or via an FS URL, using TLS::
 
-            >>> import fs
-            >>> ftp_fs = fs.open_fs('ftps://')
+            >>> ftp_fs = fs.open_fs('ftps://demo.wftpserver.com')
+
+        You can also use a non-anonymous username, and optionally a
+        password, even within a FS URL::
+
+            >>> ftp_fs = FTPFS("test.rebex.net", user="demo", passwd="password")
+            >>> ftp_fs = fs.open_fs('ftp://demo:password@test.rebex.net')
 
     """