Handle zero points in blueprint components more carefully

[martun]

I suggest to change constructors of "struct input_type" for all the components that are using EC points as inputs to convert an algebra zero point, which is normally {0, 1} to a "blueprint" version which is {0, 0}.

We have temporarily changed algebra to support {0, 0}, but it's a hack. This suggestion is a hack as well, but it's a more clear one.