setup.py: fix package definition issues
setup.py: fix package definition issues

- Don't use `provides`. This isn't officially supported and technically
  provides the same information as `name` and `version` (which are
  already present.
- Make classifiers a list rather than a tuple. For some reason this
  worked last time a package was published, but not setuptools complains
  with a strange message about invalid classifiers.

geomet/geomet,larsbutler/geomet,larsbutler/geomet,geomet/geomet