float CT stringification

[bearophile]

Fawzi Mohamed:
> I don't think that you really gain something by making the 
> weight value compiletime, just the sparsity structure (number of 
> variables) makes you gain something...

Right, the gain comes only from not doing the multiplication where the coefficient is 1, and not doing anything where it's zero.
Still, I'd like to have a CT toString(float).

Bye,
bearophile