MARCO should handle start attributes applied to elements of arrays

[casella]

In order to fix #8, MARCO should be able to handle models such as this one:

model M
  record R
    Real x;
    Real y;
  end R;
  
  R r(x(start = 1), y(start = 2));
  R[2] rv(x(start = fill(1,2)), y(start = fill(2,2)));
equation
  r = R(0,0);
  for i in 1:2 loop
    rv[i] = R(0,0);
  end for;
end M;

[mscuttari]

Fixed with e3ff1b2