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.sync2;

class Lock
{
}

const Lock lock;

static this()
{
    lock = new Lock;
}

void main()
{
    size_t id;
    synchronized(lock) id = 2;
}