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 tangotests.stdout2;

import tango.io.Stdout;

void main()
{
    Stdout.formatln("{} {} {}", "a", "b", 1.0);
}