Dawdreamer

New Plugin Processor features:
* `open_editor()`
* `load_state(filepath: str)`
* `save_state(filepath: str)`
* `can_set_bus(inputs: int, outputs: int)`
* `set_bus(inputs: int, outputs: int)`

See `tests/test_plugins.py` for more examples.

Non-breaking changes to Playback Warp Processor:
* Fix issue with when warping is disabled (close https://github.com/DBraun/DawDreamer/issues/81)
* Add new function for resetting warp markers to a steady BPM `reset_warp_markers(bpm: float)`
* Add new function for setting warp markers to a 2D array (`.warp_markers` property) (close https://github.com/DBraun/DawDreamer/issues/73)

See `tests/test_playbackwarp_processor.py` for more examples.

Breaking changes:
* Previously we encouraged using `assert` statements in conjunction with various functions such as `assert engine.load_graph(graph)`. This is now discouraged because these functions that previously returned bools will now throw errors when relevant. It is up to you to catch the errors with `try/except` blocks. The benefit is that you are no longer burdened with writing `assert` all over.

Non-breaking changes:
* Fix bug in how Faust processor handle MIDI loaded from files.
* Fix bug in Add Processor's number of output channels. It will always be stereo now.
* Add keyword arg `all_events` to `load_midi` for Plugin Processor. Default is True for backwards compatibility.
* Add Faust Processor property `faust_libraries_path` to specify where user's `.lib` files are.
* Add Faust property for release length to avoid false-positive voice stealing warnings.
* Revise Render Engine graph construction to give warning rather than error when too many signals are connected to some other node.
* Upgrade JUCE, Faust and pybind11

Thanks to everyone who filed issues and PRs.

Trying to fix pip install requirements

* Multichannel support for VSTs, Faust, and other applicable processors
* * try `synth.get_num_input_channels()` and `synth.get_num_output_channels()`
* Better macOS support for all CPU types (try `pip install dawdreamer` again!)

Minor update for pypi wheels with no code changes. This should build macOS from 10.15 but still support Apple Silicon via the "universal" build wheels.