foo-snapshot / foo-diff convenience functions

[Lawrence Velázquez]

> On Oct 20, 2016, at 4:25 PM, René J.V. Bertin <rjvbertin at gmail.com>
> wrote:
> 
>> On Thursday October 20 2016 15:38:42 Lawrence Velázquez wrote:
>> 
>> Better that than increasing the complexity of base and portfiles.
> 
> Yeah, unless someone proposes to implement something in a portgroup.
> Then all of a sudden it becomes base functionality ...

Nonsense. There's plenty of functionality currently implemented in
portfiles that would make no sense in base.

> I won't be reinventing all kinds of wheels to delay updating
> dependency declarations beyond checking for the presence of a token
> when the portgroup is being read.

¯\_(ツ)_/¯

vq