Hnet

* Fix heatmap interactive chart

* fix for setup file
* datazets added to include various example data sets
* Update in docstrings

* Fix in case columns are not unique. This is now automatically fixed by adding an underscore with a number.

* Bug fixes due to pandas
* Bug fixes in plots (integration d3blocks)
* wget replaced by internal functions
* Docstrings updated

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

Minor updates:

* Added new example to demonstrate market basket analysis.

from hnet import hnet
hn = hnet()
df = hn.import_example('grocery')
results = hn.association_learning(df)
hn.d3graph(summarize=True)
hn.d3heatmap(summarize=True)


* Update url link
* Update example in docstring
* Some code styling