[RDY] Merging vim-patch:7.4.170

Merging vim-patch:7.4.170

Problem:    Some help tags don't work with ":help". (Tim Chase)
Solution:   Add exceptions.

https://code.google.com/p/vim/source/detail?r=8122eab8fcdbbdaac62dfbf7c6458cb3e6f46b04