Add support for a scalar range node type

[green-coder]

This would allow the count-model to be more readable, which will make generating collections of the right size easier.

Proposed format:

{:type :range
 :min 1    ; inclusive, optional
 :max 3    ; inclusive, optional
 :inf -5.0 ; exclusive, optional
 :sup 5.0  ; exclusive, optional
 }

:min and :inf cannot appear at the same time in the node,
:max and :sup cannot appear at the same time in the node.