FIX: Fix examples

Closes #524.
Closes #522.

Ready for review/merge.
No, it shouldn't. This breaks support for passing in colors as strings, e.g. `black` or `#001122`. Besides, it is more explicit that, if they want it to be a `Function`, have them pass in `Function(str)` instead of just `str`. I don't see the point in doing that translation for them...