Announcing new DIP handling process

[Dicebot via Digitalmars-d-announce]

After quite some preliminary discussions and preparations, new D
Improvement Proposals handling process is finally happenning. Please
read description and explanation here:

https://github.com/dlang/DIPs

## Rationale

There are two main goals for going this way:

1) Ensure communication between language authors and DIP authors,
establish better sense of actually contributing as opposed to simply
throwing ideas into the black box.

2) Improve overall quality of DIP documents to the point where language
authors can reasonably review them without spending too much time on
trivialities.

Additional benefit I am hoping for is to have a centralized place to
subscribe to learn about all coming major changes coming to language for
those who can't keep up with NG regularly.

## Old DIPs

Right now https://github.com/dlang/DIPs repository contains archive
folder with already implemented proposals imported from wiki (please
tell me if there are any other already implemented DIPs that were not
marked as such in wiki).

All authors of existing DIPs who want to keep pursuing the idea will
have to re-submit them as a pull requests towards new repo. This is
required so that we can filter abandoned proposals and focus on
documents that have active authors backing them.

## DIP manager

I will act as a DIP manager for the time being. Please note that role of
DIP manager does not imply any decision power regarding DIP approval, it
remains an exclusive domain of language authors.