Fix VarDecls for tuples. Closes #99. I've implemented it this way since it doesn't require any changes in the frontend. However, I think having TypeTuple expressed as LLVM struct types would make much more sense and open the door to tuple lvalues.

module complex2;

void main()
{
    cdouble c = 3.0 + 0i;
    cdouble d = 2.0 + 0i;
    cdouble c1 = c + 3.0;
    cdouble c2 = c - 3.0i;
    cdouble c3 = c / 2.0;
}