[RFC] vim-patch:7.4.210

Merging vim-patch:7.4.210

Problem:    Visual block mode plus virtual edit doesn't work well with tabs.
            (Liang Li)
Solution:   Take coladd into account. (Christian Brabandt)

https://code.google.com/p/vim/source/detail?r=420fd9cb86d51a92c4307a746557e81914c6d6c4