D and expression evaluation order.

[Manfred Nowak]

Bruno Medeiros wrote

> define an evaluation order for such expressions

- if a coder wants to define an order, she/he is free to use an 
appropriate sequence of assignments
- if there is a predefined order, then
-- that predefined order must be learned by everyone
-- for every deviation of that order the appropriate sequence of 
assignments must be coded anyway

-manfred