Implement loops

[memburg]

Loops will be implemented like following:

val i = "0";

loop { // this will be transpiled as "while True:"
    when (eqs(i, "4")) {
        i = add(i, "1");
        next; // this will be transpiled as "continue"
    }
    
    println(i);
    i = add(i, "1");

    when (eqs(i, "10")) {
        out; // this will be transpiled as “break"
    }
}