Add pragma(error) and pragma(warning) to the language.

[Timon Gehr]

On 11/10/2011 08:12 PM, Justin Whear wrote:
> How would pragma(error) differ from "static assert(false,
> errorMessageHere)"?
>
>

static assert explains that the error occured because of a static 
assertion failure, pragma(error) would not do such a thing.

@topic: +1.