Fixed date to move to ddox for Phobos documentation

[Martin Nowak via Digitalmars-d]

On 06/04/2016 09:32 PM, Andrei Alexandrescu wrote:
> Sounds good to me, thanks. Delegation/lieutenantship/empowering for the
> win. I think we should also secure Martin's buy-in to make sure. -- Andrei

I'm fine with switching to ddox, could have happened a while ago.
Would be worth to switch for the auto-complete alone.

I'd want to disable or replace discourse before we make it our official
documentation. We could easily self-host some commenting functionality
if deemed necessary, but adding an unmaintained communication channel
isn't the best idea IMO.

-Martin