updated for version 7.4.165
Problem:    By default, after closing a buffer changes can't be undone.
Solution:   In the example vimrc file set 'undofile'.
Added tag v7-4-165 for changeset c82339d8fdae
updated for version 7.4.166
Problem:    Auto-loading a function for code that won't be executed.
Solution:   Do not auto-load when evaluation is off. (Yasuhiro Matsumoto)
Added tag v7-4-166 for changeset 5d03c3747121