Ploomber

- Adds Jupyter notebook extension to inject parameters when opening a
task
- Improved CLI `ploomber new`, `ploomber add` and `ploomber entry`
- Spec API documentation additions
- Support for `on_finish`, `on_failure` and `on_render` hooks in spec API
- Improved validation for DAG specs
- Several bug fixes

- Reduces the number of required dependencies
- A new option in DBAPIClient to split source with a custom separator

- Adds CLI
- New spec API to instantiate DAGs using YAML files
- NotebookRunner.debug() for debugging and .develop() for interacive
development
- Bug fixes

- PythonCallable.debug() now works in Jupyter notebooks

- PythonCallable.debug() now uses IPython debugger by default
- Improvements to Task.build() public API
- Moves hook triggering logic to Task to simplify executors
implementation
- Adds DAGBuildEarlyStop exception to signal DAG execution stop
- New option in Serial executor to turn warnings and exceptions
capture off
- Adds Product.prepare_metadata hook
- Implements hot reload for notebooks and python callables
- General clean ups for old `__str__` and `__repr__` in several modules
- Refactored ploomber.sources module and ploomber.placeholders
(previously ploomber.templates)
- Adds NotebookRunner.debug() and NotebookRunner.develop()
- NotebookRunner: now has an option to run static analysis on render
- Adds documentation for DAG-level hooks
- Bug fixes

- Bug fixes [88](https://github.com/ploomber/ploomber/issues/88), [#89](https://github.com/ploomber/ploomber/issues/89), [#90](https://github.com/ploomber/ploomber/issues/90), [#84](https://github.com/ploomber/ploomber/issues/84), [#91](https://github.com/ploomber/ploomber/issues/91)
- Modifies Env API: Env() is now Env.load(), Env.start() is now Env()
- New advanced Env guide added to docs
- Env can now be used with a context manager
- Improved DAGConfigurator API
- Deletes logger configuration in executors constructors, logging is
available via DAGConfigurator