[Bug] when using `N` block scaled by some constant with GPSR

[vytautas-a]

When generator has w*N(i) terms and we want to use GPSR - an error is raised due to lack of eigenvalues_generator property for N block.

Solution: modify uuid_to_block function so that N blocks are not assigned uuids and included in the dict of parameters passed to GPSR functions.

[dominikandreasseitz]

hm, not that easy @vytautas-a . we need the uuids in the dict, i guess this needs to be refactorted. tagging @Roland-djee