Add dependency on ipywidgets

[Seth-Rothschild]

• Henchman version: 0.0.3

Description

For notebook use, having access to ipywidgets would explode the possibilities for what diagnostics, learning and selection can do. It would be possible to do things like:

1. limit a profile to a data subset
2. toggle warning parameters with sliders
3. provide a dropdown of different sklearn models and metrics

Ultimately, this is the direction the software should move in going forward but some baby steps would be appropriate before release of the next version.