Path to v0.3.0

[rsokl]

• The bugfix caught in 481a0a2
• hydra_meta and hydra_partial -> zen_meta and zen_partial
• Implementation for zen_wrappers including support for specifying wrappers via interpolated strings
• Support for pydantic
• Support for beartype, which requires some heavy machinery on our end to do sequence-coercion
• A nice interface for customizing the defaults on builds
• The beginner-friendly make_config
• Merging and moving hydra_run and hydra_multirun #127

After these, I think this will be mark a feature-freeze on 0.3.0, which has become much more ambitious than I had expected!
Then.. docs!

[rsokl]

🎉