Generates a circular or semicircular-with-base tissue template with hexagonal cells.
TemplateCircularHoneycombCover[radius] returns a Tissue object composed of hexagonal cells with a minimum total radius as specified. The hexagons each have edges of length 1.
TemplateCircularHoneycombCover[radius, rows] - generate a semi-circular template of minimum radius on top of a base of the given number of rows. The number of rows added on the base of the semi-circle will extend at most one cell beyond the radius of the circle, so a radius n template can have a base of at most n layers.