Inherited constructor

[Andy Valencia]

What is considered the "clean" way to address this error:

```
tst60.d(7): Error: class `tst60.B` cannot implicitly generate a 
default constructor when base class `tst60.A` is missing a 
default constructor
```

Yes, this is a toy example, but it reflects something I'm doing 
in actual code.  The subclass has no state, thus it's fine to let 
the superclass take care of initialization.  Do I really need a 
shim like this:

```d
     this(int val) {
         super(val);
     }
```

In my class B just to placate the compiler?  Is this considered 
the idiomatic way to deal with such a class organization?

```d
class A {
     int v;
     this(int val) {
         this.v = val;
     }
}
class B : A {
     int myfunc() {
         return this.v;
     }
}
int main() {
     auto b = new B(1);
     return b.myfunc();
}
```