Add face for col-highlight (used by col-highlight and crosshair)

[Col-Highlight](http://www.emacswiki.org/emacs/col-highlight.el) and [Crosshairs](http://www.emacswiki.org/emacs/col-highlight.el) makes use of col-highlight face to highlight the current column.

It would be nice if this was the exact same as `hl-line` and is provided by the theme itself.