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 sqrts;

import tango.stdc.math;

double sqrt(double d)
{
    return tango.stdc.math.sqrt(d);
}

void main()
{
}