Updated by JohnWMcC to v1.4.1

Extensive rewrite which:
Adds new Class for Sphere based on existing Dome
Adds ability to choose number of segments for shapes based on a circle, not just the fixed default (usually 24 in original)
Extends Pyramid to use any regular polygon base, not just a square
Sets initial default sizes based on model units, to one unit for most, 10 units for mm or cm.
Offers default size settings from previous use of each shape