Add VISUAL to several snippets

I recently watch Drew Neil's talk at [VimLondon](http://vimeo.com/102142402) where he introduced me to this feature. This doesn't change the functionality at all for the usual case, so I thought it would be worth adding to the functionality for when you want it.
I think usually the pattern $0${VISUAL} is better. Why would you want to select all the stuff you wrapped?