[RFC] vim-patch:7.4.407

Problem:    Inserting text for Visual block mode, with cursor movement, repeats the wrong text. (Aleksandar Ivanov)
Solution:   Reset the update_Insstart_orig flag. (Christian Brabandt)

https://code.google.com/p/vim/source/detail?r=v7-4-407

It's strange that git thinks `test39.ok` is a binary file. Google displays the diff correctly.
`linetabsize` returns an `int` which is cast to the type of `Insstart_textlen`. Although `colnr_T` is defined as `int`, I like the explicit cast here.
Otherwise line https://github.com/neovim/neovim/blob/fe446c86cf752961fab84f92aa4956aaa4dc3f6f/src/nvim/edit.c#L339 should be changed too.