Closes https://github.com/pyodide/pyodide/issues/604

This creates an installable `pyodide-build` Python package that we can also upload to PyPi under https://pypi.org/project/pyodide-build/ (currently uploaded the dev version to reserve the name).

There is also the identically named `pyodide-build` CLI command which replaces `bin/pyodide`.

The short term goals is to use fewer hacks with `PATH` and `PYTHONPATH`. Long term goal make it a user facing interface for building packages instead of the Makefile.
Create an installable pyodide-build package. Closes https://github.com/pyodide/pyodide/issues/604

This creates an installable `pyodide-build` Python package that we can also upload to PyPi under https://pypi.org/project/pyodide-build/ (currently uploaded the dev version to reserve the name).

There is also the identically named `pyodide-build` CLI command which replaces `bin/pyodide`.

The short term goals is to use fewer hacks with `PATH` and `PYTHONPATH`. Long term goal make it a user facing interface for building packages instead of the Makefile.
# Python API

Backward compatibility of the API is not guaranteed at this point.

**Javascript Modules**

By default there are two Javascript modules. More can be added with
{any}`pyodide.registerJsModule`. You can import these modules using the Python
``import`` statement in the normal way.

```{eval-rst}
.. list-table::

   *  - ``js``
      - The global Javascript scope.
   *  - :js:mod:`pyodide_js <pyodide>`
      - The Javascript Pyodide module.
```

```{eval-rst}
.. currentmodule:: pyodide

.. automodule:: pyodide
   :members:
   :autosummary:
   :autosummary-no-nesting:
```

# Python API

Backward compatibility of the API is not guaranteed at this point.

**Javascript Modules**

By default there are two Javascript modules. More can be added with
{any}`pyodide.registerJsModule`. You can import these modules using the Python
``import`` statement in the normal way.

```{eval-rst}
.. list-table::

   *  - ``js``
      - The global Javascript scope.
   *  - :js:mod:`pyodide_js <pyodide>`
      - The Javascript Pyodide module.
```

```{eval-rst}
.. currentmodule:: pyodide

.. automodule:: pyodide
   :members:
   :autosummary:
   :autosummary-no-nesting:
```
