fix(modeling): expose hullPoints2 and hullPoints3

[z3dev]

These changes expose hullPoints2() and hullPoints3(), which will allow users to use these functions to create custom geometries, etc.

NOTE: hullPoints3() is new, and hullGeom3() has been changed to use this function.

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[z3dev]

@platypii @hrgdavor please review. all comments welcome.

[platypii]

Looks good, seems useful