Note CRS other than CRS84 are not recommended.

I've done this in the CRS section using the term NOT RECOMMENDED
and also mentioned it in the new abstract.

I-D name changed to "draft-butler-geojson-00".

Added links to the mailing list and GitHub repo in the contributors
section.
Recommend our default CRS.
Merge branch 'master' of github.com:geojson/draft-geojson
Make the default crs a SHOULD.

As per comments on #15.

Also add address for Sean and restore address for Stefan.
Named and linked CRS are restored to the document.

By saying that the default SHOULD be used, the use of other
named or linked crs is implicitly NOT RECOMMENDED.

Also remove uncited references.
Improve specification of non-default CRS.

Bump the recommendations for best practice CRS acquistion up above
the CRS object details.
Merge pull request #15 from sgillies/master

Note CRS other than CRS84 are not recommended.