supporting DMD-1.016 and DMD-2.000 with the same source code

[Sean Kelly]

Thomas Kuehne wrote:
> 
> 4) class invariants
> ===================
> 
> This is the only real trouble spot so far. DMD-1 uses
> 	invariant{ ... assert(...); ... }
> however DMD-2 uses
> 	invariant(){ ... assert(...); ... }

Well that's unfortunate.  I don't suppose unittest has gotten 
parenthesis as well?


Sean