Add superball form factor (Trac #1265)

[sasview-bot]

A superball represents a cube with rounded edges and transforms from a sphere to a cube by a single parameter with the definition x^(2p) + y^(2p) + z^(2p) <= R^(2p).

Migrated from http://trac.sasview.org/ticket/1265

{
    "status": "new",
    "changetime": "2019-03-29T12:33:25",
    "_ts": "2019-03-29 12:33:25.480055+00:00",
    "description": "A superball represents a cube with rounded edges and transforms from a sphere to a cube by a single parameter with the definition x^(2p) + y^(2p) + z^(2p) <= R^(2p).",
    "reporter": "DomiDre",
    "cc": "",
    "resolution": "",
    "workpackage": "SasModels New Model",
    "time": "2019-03-29T12:14:08",
    "component": "sasmodels",
    "summary": "Add superball form factor",
    "priority": "minor",
    "keywords": "superball",
    "milestone": "sasmodels 1.0",
    "owner": "DomiDre",
    "type": "enhancement"
}

[sasview-bot]

Trac update at 2019/03/29 12:33:25: DomiDre changed milestone from "SasView 5.0.0" to "sasmodels 1.0"

[dehoni]

The model has been tested and is ready to be released after the reference is published and the documentation completed.