Use different slider ranges for Topomath

[jonwetzel]

When authoring a parameter node, author should be able to pick the range for the slider in the graph window (max value and min value). For positive parameters, the slider range defaults to 0 to 10x the parameter value. For negative parameters, the slider range defaults to 10x the value of the parameter to 0. For custom ranges entered by the author, the max value must be greater than or equal to the min value, and include the parameter value.

We need to have a solution for the case where we end up dividing by zero.

[vanlehn]

Not using sliders for topomath, so downgrade to wishlist