Add logic operators

[Specy]

Logic operators should be added like the OR, AND, IMPLIES, NOT, and also the relative blocks for it, this could be something like:

and(i in 0..5) { x_i } ==> false

or

x_0 & x_1 | x_2 & !x_3

constraints are written as a single expression, and all constraints must be true for the model to be valid, all variables inside this constraints must be defined as booleans