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 bug23;
extern(C) int printf(char*, ...);

void main()
{
    int i;
    delegate {
        i++;
        delegate {
            i++;
        }();
    }();
    printf("%d\n", i);
    assert(i == 2);
}