Deprecate `gid`/`sgid`/`global_id`/`signed_global_id`

Did a quick spike to see how we can gracefully handle the rename, but it took more code than I thought, so I am not sure if it's worth the effort. However I suppose we will cut a 1.0 release to go out with 4.2.0.final, so not like this code is staying for a long time anyway.

Feel free to reject this and just rename it if you don't think it's worth the trouble. This is still < 1.0 so I suppose it's fair game either way.

Closes #34