Repurpose qgrid demo notebooks

[richardlin047]

Section from README.rst

Running the demo notebooks locally
----------------------------------

There are a couple of demo notebooks in the `qgrid-notebooks <https://github.com/quantopian/qgrid-notebooks/>`_ repository
which will help you get familiar with the functionality that qgrid provides. Here are the steps to clone the
qgrid-notebooks repository and open a demo notebook:

#. Install qgrid by following the instructions in the `Installation`_ section above, if you haven't already

#. Clone the qgrid-notebooks repository from GitHub::

    git clone https://github.com/quantopian/qgrid-notebooks.git

#. Install the dev requirements for the repository and start the notebook server::

    cd qgrid-notebooks
    pip install -r requirements_dev.txt
    jupyter notebook

#. Click on one of the two notebooks (`index.ipynb <https://github.com/quantopian/qgrid-notebooks/blob/master/index.ipynb>`_ or `experimental.ipynb <https://github.com/quantopian/qgrid-notebooks/blob/master/experimental.ipynb>`_) that you see listed in the notebook UI in your browser.

Also

See the `events notebook <https://mybinder.org/v2/gh/quantopian/qgrid-notebooks/master?filepath=events.ipynb>`_ for more examples of using these new API methods.

[richardlin047]

Also create own binder demo