Better go support

[dolanor]

Hi,

There is a PR about adding some go keyword to the list. I've done that on my side too, but I was bugged by the fact that package names were not ignored either, and this cripples the view by non important color.
My VimL coding skills are pretty low, so I don't really know what to do.

Would it be to add those package names to the ignore list dynamically by file?
Is there any example of how to do that?