D3graph

* added node text coloring: See example over [here](https://erdogant.github.io/d3graph/pages/html/Core_Functionalities.html#node-text-color)
* Solved 22

* Removed scikit-learn from the default setup and requirements to make it more lightweight. In case scikit-learn is required (when scaler is minmax, a message is shown).

* added on click functionality. With the `click `input parameter, nodes can be highlighted.


from d3graph import d3graph
d3 = d3graph()
adjmat, df = d3.import_example('karate')
d3.graph(adjmat, color='cluster')

Specify click event
html = d3.show(click={'fill': 'green', 'stroke': 'black', 'size': 2, 'stroke-width': 2})

No event
html = d3.show(click=None)

* Minor bug fixes

* `sklearn` changed into `scikit-learn` in both requirements and setup file.

* Fix for hex-colors when using color='cluster'.
* input parameter `group `is changed into `color`.