[CF-metadata] CF-1.0 released

[Jonathan Gregory]

We're very pleased to announce that CF-1.0 is released, the first non-beta
version of the CF standard. It's more than two years since the first public
beta version, and thanks are due to many people for the work that has been
done on improving the document since then.

CF-1.0 will not be changed any more. We will begin to develop CF-1.1, which
will include various changes which have been discussed and agreed on the email
list, such as the treatment of forecast time, and how to record operations
like covariance in cell_methods. Proposals for further additions are welcome
as usual on the email list.

Jonathan Gregory