A matplotlib metapackage

[marcelm]

Now that matplotlib 3.0.0 has been released, I’d like to push forward the idea of splitting a matplotlib-core package that does not depend on pyqt off of matplotlib. This was discussed on conda-forge/matplotlib-feedstock#2 and conda-forge/matplotlib-feedstock#157. My suggestion was to rename matplotlib(-feedstock) to matplotlib-core(-feedstock), remove the pyqt dependency from it, and to add a matplotlib metapackage that depends on the new matplotlib-core and pyqt.

This pull request adds the metapackage, but could of course only be merged after the rename.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipes/matplotlib) and found some lint.

Here's what I've got...

For recipes/matplotlib:

• The recipe could do with some maintainers listed in the extra/recipe-maintainers section.
• The recipe must have some tests.
• Feedstock with the same name exists in conda-forge

[ocefpaf]

@marcelm let us try the split-package approach instead of another feedstock. I add a comment on your mpl PR about that.

[marcelm]

Thanks, I did not realize split packages would work for that. This will also make it easier to keep the version numbers in sync.