Added sensible Circle.ex value when input is scalar input values

Scalar input data like [0, 1, 2 ...] would lose the information related to the input values when converted to Circle even after we added the ex dictionary. The input values is now stored in the ex dict when the input is a simple scalar value. That allows for downstream to display sensible text defaults when drawing the circles.

See https://github.com/elmotec/circlify#example for an example.