Replace core language HexStrings with library entity

[via Digitalmars-d]

On Sunday, 15 March 2015 at 19:47:06 UTC, Walter Bright wrote:
> HexStrings:
>
>     http://dlang.org/lex.html#HexString
>
> They're rarely used, but very useful when needed. But, as the 
> octal literals have shown, they can be easily replaced with a 
> library template:
>
>     x"00 FBCD 32FD 0A"
>
> becomes:
>
>     hex!"00 FBCD 32FD 0A"
>
> It'll simplify the core language slightly.
>
> Thoughts? Anyone want to write the hex template? Any other 
> ideas on things that can removed from the core language and 
> replaced with library entities?

Can we make it so it returns a ubyte[]?