- Remove `Heroics.cli_from_schema_url` and related tests.
- Remove `Heroics.client_from_schema_url` and related tests.
- Update the README to reflect reality.
Merge pull request #14 from heroku/remove-schema-url-support

- Remove `Heroics.cli_from_schema_url` and related tests.
- Remove `Heroics.client_from_schema_url` and related tests.
- Update the README examples to explicitly load the schema instead of
  expecting to use one of the now-deleted methods.