Remove many "versionchanged" items that didn't use the official markup,
but just some text embedded in the docs.

Also remove paragraph about implicit relative imports from tutorial.
diff --git a/Doc/library/ftplib.rst b/Doc/library/ftplib.rst
index 4ce8893..41bdcd8 100644
--- a/Doc/library/ftplib.rst
+++ b/Doc/library/ftplib.rst
@@ -187,9 +187,8 @@
 
 .. method:: FTP.set_pasv(boolean)
 
-   Enable "passive" mode if *boolean* is true, other disable passive mode.  (In
-   Python 2.0 and before, passive mode was off by default; in Python 2.1 and later,
-   it is on by default.)
+   Enable "passive" mode if *boolean* is true, other disable passive mode.
+   Passive mode is on by default.
 
 
 .. method:: FTP.storbinary(command, file[, blocksize, callback])