Add the ability for custom functions to create dummy outcome (#122)

* add the ability for custom functions to create dummy outcome

* replace outcome_prediction_function by outcome_function

* fix spelling mistakes in dummy_outcome_refuter

* add type check support

* add test for dummy_outcome_refuter

* example for dummy outcome refuter

A detailed example on how to use the dummy outcome refuter.

* rename the file to match naming convention

* add support for pandas series and dataframes

* add missing pandas dependency

* rename the outcome function

* change the title of the notebook

* convert the title to Camel Case

* fix the p values in the demo

* undo p-value change and fix spellings