Add the Simon's problem to the list of examples

[dmoranj]

Add the Simon's problem to the list of examples, along with the documentation and changes needed in the library.

[dmoranj]

First task will be to create a function that, given an integer, returns a Uf unitary operator that, applied to an input and an output |x> |0> leads to the result |x> |f(x)>, with f(x) verifiying the following:

f(x) = f(y) <=> x = y + a

For a constant a that is built within the operator itself.