Plot histogram of outlier scores

[hannah-rae]

It would be helpful for deciding what threshold to use for reviewing outliers to see a distribution of the outlier scores for each algorithm. This module would generate a histogram of outlier scores.

As a side note, #24 specifies the number of outliers to record in the subset. It could also be useful to specify a threshold, though this would be algorithm-dependent (unless the threshold was based on the data, e.g., 2 std deviations or similar).

[hannah-rae]

@vinr515 I think we can close this now, but it would be good for some others to try out the functionality before closing to make sure it works across the use cases.

[hannah-rae]

@vinr515 I tried running this and it works great with no parameters but I get the following error when I use the bins parameter:
TypeError: _run() got multiple values for argument 'bins'