new extension: boyer-moore search algorithm variants

[Paolo Carlini]

Paolo Carlini wrote:

> I don't know, sizeof came to my mind, but I'm not sure it guarantees 
> that we have the right, very simple, properties for the type, I think 
> PODness is already too much, but I'd like to be wrong, because in that 
> case is_pod + sizeof would do the job.

I would say, let's use is_integral + sizeof and be done with it.

Paolo.