Union with Non-Intersection Polygons

[tp]

Probably related to #9:

union of non-intersecting polygons returns null here, but returns the input polygons with "martinez".

> m.union([ pencilPolygon.map(p2arr) ], [ eraserPolygon.map(p2arr) ]);
[ [ [ 0.11612903225806452, 0.33455451259745367 ],
    [ 0.11720430107526882, 0.33455451259745367 ],
    [ 0.11720430107526882, 0.33064826259745367 ],
    [ 0.11612903225806452, 0.33064826259745367 ] ],
  [ [ 0.14516129032258066, 0.4109600939072074 ],
    [ 0.14623655913978495, 0.4109600939072074 ],
    [ 0.14623655913978495, 0.3718975939072074 ],
    [ 0.14516129032258066, 0.3718975939072074 ] ] ]
> gh.union(pencilPolygon, eraserPolygon)
null

[w8r]

I don't know, logic probably requires that it would return both polygons