Please integrate build framework into the compiler

[Christopher Wright]

dsimcha wrote:
> 1.  std.traits could offer a way to get a tuple of all derived classes,
> essentially the opposite of BaseTypeType.
> 2.  Since DMD would know about all derived classes when compiling the base class,
> it would be feasible to allow templates to add virtual functions to classes.
> IMHO, this would be an absolute godsend, as it is currently a _huge_ limitation of
> templates.
> 3.  For the same reason, methods calls to classes with no derived classes could be
> made directly instead of through the vtable.

This is only if there is no dynamic linking.