Manifest constants (was const again)

[Walter Bright]

Oskar Linde wrote:
> Like others, I propose that manifest constants use the alias keyword. 
> Alias is perfect for this.

alias does make sense up to a point, and that point is:

	alias int x = 3;

That makes no sense in the light of what alias currently does. Manifest 
constants are not untyped, although their type can often be inferred 
from their initializer, just like auto declarations.