Idea for easier development

[bezlant]

@MikhailKuzntsov1 @AndreyZhelannikov
I suggest to convert all our functions into 128 bit format or even bigger for the ease of working with overflows. We can simply do all the math operations and if it overflows we simply make our number fit into 96 bits (dividing and abs value by 10) + bank rounding.
This should work and will make our functions a lot simpler, we just have to revamp the logic of the binary API a bit :)