Don't highlight +/- columns in patches (configurable) (take 2)

[dirkwallenstein]

The highlighting of the +/- column was bothering me to the point where I turned it off completely. You often see patches when using vim-fugitive. So this will allow you to configure filetypes where the first and second column won't get highlighted.

I use the color link to switch to faint colors in sessions where it doesn't matter and to toggle between colors. I think it's useful, too.

[bitc]

Thanks, I'll try to look at this when I have some time