[CF-metadata] Use of cf_role attribute

Hi All, I've noticed some ambiguity in the CF document around the use of the "cf_role" attribute which I think needs clarification. In Appendix A it states that the *cf_role* attribute is valid for use on a coordinate variable only, however, in virtually, if not all, the examples in Appendix

[CF-metadata] New Github issue - adding support for string type

I've added a pull request and issue on Github for a change to Chapter 2 of the Conventions that adds support for the *string* data type in variables. Trac is down right now, so there is no Trac ticket. You can see the issue and pull request at Issue - https://github.com/cf-convention/cf-convention